Urbit Developers
  • Hoon

    • Overview
    • Cheat Sheet
    • Irregular forms
    • Hoon Errors
    • Hoon Style Guide
    • Basic Types
    • Advanced Types
    • Auras
    • Arvo
    • Standard Library

      • 1a: Basic Arithmetic
      • 1b: Tree Addressing
      • 1c: Molds and Mold-Builders
      • 2a: Unit Logic
      • 2b: List Logic
      • 2c: Bit Arithmetic
      • 2d: Bit Logic
      • 2e: Insecure Hashing
      • 2f: Noun Ordering
      • 2g: Unsigned Powers
      • 2h: Set Logic
      • 2i: Map Logic
      • 2j: Jar and Jug Logic
      • 2k: Queue Logic
      • 2l: Container from Container
      • 2m: Container from Noun
      • 2n: Functional Hacks
      • 2o: Normalizing Containers
      • 2p: Serialization
      • 2q: Molds and Mold-Builders
      • 3a: Modular and Signed Ints
      • 3b: Floating Point
      • 3c: Urbit Time
      • 3d: SHA Hash Family
      • 3e: AES encryption (Removed)
      • 3f: Scrambling
      • 3g: Molds and Mold-Builders
      • 4a: Exotic Bases
      • 4b: Text Processing
      • 4c: Tank Printer
      • 4d: Parsing (Tracing)
      • 4e: Parsing (Combinators)
      • 4f: Parsing (Rule-Builders)
      • 4g: Parsing (Outside Caller)
      • 4h: Parsing (ASCII Glyphs)
      • 4i: Parsing (Useful Idioms)
      • 4j: Parsing (Bases and Base Digits)
      • 4k: Atom Printing
      • 4l: Atom Parsing
      • 4m: Formatting Functions
      • 4n: Virtualization
      • 4o: Molds
      • 5a: Compiler Utilities
      • 5b: Macro Expansion
      • 5c: Compiler Backend & Prettyprinter
      • 5d: Parser
      • 5e: Molds and mold builders
      • 5f: Profiling support
      • Runes

        • Constants (Atoms and Strings)
        • + lus · Arms
        • | bar · Cores
        • $ buc · Structures
        • % cen · Calls
        • : col · Cells
        • . dot · Nock
        • / fas · Imports
        • ^ ket · Casts
        • ; mic · Make
        • ~ sig · Hints
        • = tis · Subject
        • ? wut · Conditionals
        • ! zap · Wild
        • --, == Terminators
        • Limbs and wings

          • Limbs
          • Wings
          • Zuse

            • 2d(1-5): To JSON, Wains
            • 2d(6): From JSON
            • 2d(7): From JSON (unit)
            • 2e(2-3): Print & Parse JSON
            • 2m: Ordered Maps
          • Arvo

            • Overview
            • Ames

              • Overview
              • Cryptography
              • API Reference
              • Scry Reference
              • Data Types
              • Behn

                • Overview
                • API Reference
                • Scry Reference
                • Examples
                • Clay

                  • Overview
                  • Architecture
                  • Using Clay
                  • Data Types
                  • Scry Reference
                  • API Reference
                  • Examples
                  • Marks

                    • Overview
                    • Writing Marks
                    • Using Marks
                    • Examples
                  • Dill

                    • Overview
                    • API Reference
                    • Scry Reference
                    • Data Types
                    • Eyre

                      • Overview
                      • External API Reference
                      • Internal API Reference
                      • Scry Reference
                      • Data Types
                      • Guide
                      • Gall

                        • Overview
                        • API Reference
                        • Data Types
                        • Threads Reference
                        • Iris

                          • Overview
                          • API Reference
                          • Data Types
                          • Example
                          • Jael

                            • Overview
                            • API Reference
                            • Scry Reference
                            • Data Types
                            • Examples
                            • Khan

                              • Overview
                              • API Reference
                              • Data Types
                              • Example
                              • Threads

                                • Overview
                                • HTTP API
                                • Reference
                                • Gall

                                  • Start Thread
                                  • Take Result
                                  • Take Facts
                                  • Stop Thread
                                  • Poke Thread
                                  • Examples

                                    • Fetch JSON
                                    • Child Thread
                                    • Main-loop
                                    • Poke Agent
                                    • Scry
                                    • Take Fact
                                  • Concepts

                                    • Scries
                                    • Subscriptions
                                    • Tutorials

                                      • Move Trace
                                      • Reference

                                        • Cryptography
                                        • Filesystem Hierarchy
                                      • Nock

                                        • Nock Definition
                                        • Explanation
                                        • Example
                                        • Implementations
                                        • Vere

                                          • C Runtime System
                                          • Land of Nouns
                                          • API overview by prefix
                                          • C in Urbit
                                          • Writing Jets
                                          • Cryptography
                                          • Azimuth

                                            • Overview
                                            • Urbit HD Wallet
                                            • Azimuth Data Flow
                                            • Azimuth.eth
                                            • Ecliptic.eth
                                            • Advanced Azimuth Tools
                                            • Life and Rift
                                            • Layer 2

                                              • Layer 2 Overview
                                              • Layer 2 Actions
                                              • Transaction Format
                                              • Rollers
                                              • Roller HTTP RPC-API
                                              • Custom Roller Tutorial
                                            • Glossary

                                              • Agent
                                              • Ames
                                              • API
                                              • Aqua
                                              • Arm
                                              • Arvo
                                              • Atom
                                              • Aura
                                              • Aural ASCII
                                              • Azimuth
                                              • Battery
                                              • Behn
                                              • Bowl
                                              • Bridge
                                              • Bunt
                                              • Card
                                              • Case
                                              • Cask
                                              • Cell
                                              • Censures
                                              • Claims
                                              • Clay
                                              • Cold atom
                                              • Comet
                                              • Commit
                                              • Cons
                                              • Context
                                              • Cord
                                              • Core
                                              • Delegated Sending
                                              • Desk
                                              • Dill
                                              • Document Proposal
                                              • Dojo
                                              • Door
                                              • Double-boot
                                              • Dry Gate
                                              • Duct
                                              • Ecliptic
                                              • Entropy
                                              • Event Log
                                              • Eyre
                                              • Face
                                              • Fact
                                              • Foo Bar Baz
                                              • Galaxy
                                              • Gall
                                              • Garden
                                              • Gate
                                              • Generator
                                              • Gift
                                              • Glob
                                              • HD Wallet
                                              • Helm
                                              • Hood
                                              • Hoon
                                              • Invite Tree
                                              • Iris
                                              • Jael
                                              • Jet
                                              • Kelvin versioning
                                              • Kelvin versioning
                                              • Keyfile
                                              • Keywords
                                              • Khan
                                              • Kiln
                                              • Landscape
                                              • Leg
                                              • List
                                              • Loobean
                                              • Lull
                                              • Mark
                                              • Metals
                                              • Mold
                                              • Monad
                                              • Moon
                                              • Move
                                              • Nock
                                              • Noun
                                              • ~
                                              • OTA Updates
                                              • Path Prefix
                                              • Path
                                              • @p
                                              • Payload
                                              • Peek
                                              • pH
                                              • Pier
                                              • Pill
                                              • Planet
                                              • Poke
                                              • Proxies
                                              • Replay
                                              • Factory Reset
                                              • Roller
                                              • Naive rollups
                                              • Rune
                                              • Runtime
                                              • Sail
                                              • Sample
                                              • Scry
                                              • Senate
                                              • Ship
                                              • Slam
                                              • Spider
                                              • Sponsor
                                              • Star
                                              • String
                                              • Subject Oriented Programming
                                              • Subject
                                              • Subscription
                                              • Tape
                                              • Thread
                                              • Trap
                                              • Udon
                                              • Upgrade Proposal
                                              • Userspace
                                              • Vane
                                              • Vase
                                              • Vere
                                              • Voting
                                              • Warm atom
                                              • Wet Gate
                                              • Wing
                                              • Wire
                                              • Wrapper
                                              • ~zod
                                              • Zuse
                                              • Additional

                                                • Cryptography
                                                • Mips (Maps of Maps)
                                                • Software Distribution

                                                  • Overview
                                                  • Docket File
                                                  • Glob
                                                Urbit Developers
                                                • Hoon

                                                  • Overview
                                                  • Cheat Sheet
                                                  • Irregular forms
                                                  • Hoon Errors
                                                  • Hoon Style Guide
                                                  • Basic Types
                                                  • Advanced Types
                                                  • Auras
                                                  • Arvo
                                                  • Standard Library

                                                    • 1a: Basic Arithmetic
                                                    • 1b: Tree Addressing
                                                    • 1c: Molds and Mold-Builders
                                                    • 2a: Unit Logic
                                                    • 2b: List Logic
                                                    • 2c: Bit Arithmetic
                                                    • 2d: Bit Logic
                                                    • 2e: Insecure Hashing
                                                    • 2f: Noun Ordering
                                                    • 2g: Unsigned Powers
                                                    • 2h: Set Logic
                                                    • 2i: Map Logic
                                                    • 2j: Jar and Jug Logic
                                                    • 2k: Queue Logic
                                                    • 2l: Container from Container
                                                    • 2m: Container from Noun
                                                    • 2n: Functional Hacks
                                                    • 2o: Normalizing Containers
                                                    • 2p: Serialization
                                                    • 2q: Molds and Mold-Builders
                                                    • 3a: Modular and Signed Ints
                                                    • 3b: Floating Point
                                                    • 3c: Urbit Time
                                                    • 3d: SHA Hash Family
                                                    • 3e: AES encryption (Removed)
                                                    • 3f: Scrambling
                                                    • 3g: Molds and Mold-Builders
                                                    • 4a: Exotic Bases
                                                    • 4b: Text Processing
                                                    • 4c: Tank Printer
                                                    • 4d: Parsing (Tracing)
                                                    • 4e: Parsing (Combinators)
                                                    • 4f: Parsing (Rule-Builders)
                                                    • 4g: Parsing (Outside Caller)
                                                    • 4h: Parsing (ASCII Glyphs)
                                                    • 4i: Parsing (Useful Idioms)
                                                    • 4j: Parsing (Bases and Base Digits)
                                                    • 4k: Atom Printing
                                                    • 4l: Atom Parsing
                                                    • 4m: Formatting Functions
                                                    • 4n: Virtualization
                                                    • 4o: Molds
                                                    • 5a: Compiler Utilities
                                                    • 5b: Macro Expansion
                                                    • 5c: Compiler Backend & Prettyprinter
                                                    • 5d: Parser
                                                    • 5e: Molds and mold builders
                                                    • 5f: Profiling support
                                                    • Runes

                                                      • Constants (Atoms and Strings)
                                                      • + lus · Arms
                                                      • | bar · Cores
                                                      • $ buc · Structures
                                                      • % cen · Calls
                                                      • : col · Cells
                                                      • . dot · Nock
                                                      • / fas · Imports
                                                      • ^ ket · Casts
                                                      • ; mic · Make
                                                      • ~ sig · Hints
                                                      • = tis · Subject
                                                      • ? wut · Conditionals
                                                      • ! zap · Wild
                                                      • --, == Terminators
                                                      • Limbs and wings

                                                        • Limbs
                                                        • Wings
                                                        • Zuse

                                                          • 2d(1-5): To JSON, Wains
                                                          • 2d(6): From JSON
                                                          • 2d(7): From JSON (unit)
                                                          • 2e(2-3): Print & Parse JSON
                                                          • 2m: Ordered Maps
                                                        • Arvo

                                                          • Overview
                                                          • Ames

                                                            • Overview
                                                            • Cryptography
                                                            • API Reference
                                                            • Scry Reference
                                                            • Data Types
                                                            • Behn

                                                              • Overview
                                                              • API Reference
                                                              • Scry Reference
                                                              • Examples
                                                              • Clay

                                                                • Overview
                                                                • Architecture
                                                                • Using Clay
                                                                • Data Types
                                                                • Scry Reference
                                                                • API Reference
                                                                • Examples
                                                                • Marks

                                                                  • Overview
                                                                  • Writing Marks
                                                                  • Using Marks
                                                                  • Examples
                                                                • Dill

                                                                  • Overview
                                                                  • API Reference
                                                                  • Scry Reference
                                                                  • Data Types
                                                                  • Eyre

                                                                    • Overview
                                                                    • External API Reference
                                                                    • Internal API Reference
                                                                    • Scry Reference
                                                                    • Data Types
                                                                    • Guide
                                                                    • Gall

                                                                      • Overview
                                                                      • API Reference
                                                                      • Data Types
                                                                      • Threads Reference
                                                                      • Iris

                                                                        • Overview
                                                                        • API Reference
                                                                        • Data Types
                                                                        • Example
                                                                        • Jael

                                                                          • Overview
                                                                          • API Reference
                                                                          • Scry Reference
                                                                          • Data Types
                                                                          • Examples
                                                                          • Khan

                                                                            • Overview
                                                                            • API Reference
                                                                            • Data Types
                                                                            • Example
                                                                            • Threads

                                                                              • Overview
                                                                              • HTTP API
                                                                              • Reference
                                                                              • Gall

                                                                                • Start Thread
                                                                                • Take Result
                                                                                • Take Facts
                                                                                • Stop Thread
                                                                                • Poke Thread
                                                                                • Examples

                                                                                  • Fetch JSON
                                                                                  • Child Thread
                                                                                  • Main-loop
                                                                                  • Poke Agent
                                                                                  • Scry
                                                                                  • Take Fact
                                                                                • Concepts

                                                                                  • Scries
                                                                                  • Subscriptions
                                                                                  • Tutorials

                                                                                    • Move Trace
                                                                                    • Reference

                                                                                      • Cryptography
                                                                                      • Filesystem Hierarchy
                                                                                    • Nock

                                                                                      • Nock Definition
                                                                                      • Explanation
                                                                                      • Example
                                                                                      • Implementations
                                                                                      • Vere

                                                                                        • C Runtime System
                                                                                        • Land of Nouns
                                                                                        • API overview by prefix
                                                                                        • C in Urbit
                                                                                        • Writing Jets
                                                                                        • Cryptography
                                                                                        • Azimuth

                                                                                          • Overview
                                                                                          • Urbit HD Wallet
                                                                                          • Azimuth Data Flow
                                                                                          • Azimuth.eth
                                                                                          • Ecliptic.eth
                                                                                          • Advanced Azimuth Tools
                                                                                          • Life and Rift
                                                                                          • Layer 2

                                                                                            • Layer 2 Overview
                                                                                            • Layer 2 Actions
                                                                                            • Transaction Format
                                                                                            • Rollers
                                                                                            • Roller HTTP RPC-API
                                                                                            • Custom Roller Tutorial
                                                                                          • Glossary

                                                                                            • Agent
                                                                                            • Ames
                                                                                            • API
                                                                                            • Aqua
                                                                                            • Arm
                                                                                            • Arvo
                                                                                            • Atom
                                                                                            • Aura
                                                                                            • Aural ASCII
                                                                                            • Azimuth
                                                                                            • Battery
                                                                                            • Behn
                                                                                            • Bowl
                                                                                            • Bridge
                                                                                            • Bunt
                                                                                            • Card
                                                                                            • Case
                                                                                            • Cask
                                                                                            • Cell
                                                                                            • Censures
                                                                                            • Claims
                                                                                            • Clay
                                                                                            • Cold atom
                                                                                            • Comet
                                                                                            • Commit
                                                                                            • Cons
                                                                                            • Context
                                                                                            • Cord
                                                                                            • Core
                                                                                            • Delegated Sending
                                                                                            • Desk
                                                                                            • Dill
                                                                                            • Document Proposal
                                                                                            • Dojo
                                                                                            • Door
                                                                                            • Double-boot
                                                                                            • Dry Gate
                                                                                            • Duct
                                                                                            • Ecliptic
                                                                                            • Entropy
                                                                                            • Event Log
                                                                                            • Eyre
                                                                                            • Face
                                                                                            • Fact
                                                                                            • Foo Bar Baz
                                                                                            • Galaxy
                                                                                            • Gall
                                                                                            • Garden
                                                                                            • Gate
                                                                                            • Generator
                                                                                            • Gift
                                                                                            • Glob
                                                                                            • HD Wallet
                                                                                            • Helm
                                                                                            • Hood
                                                                                            • Hoon
                                                                                            • Invite Tree
                                                                                            • Iris
                                                                                            • Jael
                                                                                            • Jet
                                                                                            • Kelvin versioning
                                                                                            • Kelvin versioning
                                                                                            • Keyfile
                                                                                            • Keywords
                                                                                            • Khan
                                                                                            • Kiln
                                                                                            • Landscape
                                                                                            • Leg
                                                                                            • List
                                                                                            • Loobean
                                                                                            • Lull
                                                                                            • Mark
                                                                                            • Metals
                                                                                            • Mold
                                                                                            • Monad
                                                                                            • Moon
                                                                                            • Move
                                                                                            • Nock
                                                                                            • Noun
                                                                                            • ~
                                                                                            • OTA Updates
                                                                                            • Path Prefix
                                                                                            • Path
                                                                                            • @p
                                                                                            • Payload
                                                                                            • Peek
                                                                                            • pH
                                                                                            • Pier
                                                                                            • Pill
                                                                                            • Planet
                                                                                            • Poke
                                                                                            • Proxies
                                                                                            • Replay
                                                                                            • Factory Reset
                                                                                            • Roller
                                                                                            • Naive rollups
                                                                                            • Rune
                                                                                            • Runtime
                                                                                            • Sail
                                                                                            • Sample
                                                                                            • Scry
                                                                                            • Senate
                                                                                            • Ship
                                                                                            • Slam
                                                                                            • Spider
                                                                                            • Sponsor
                                                                                            • Star
                                                                                            • String
                                                                                            • Subject Oriented Programming
                                                                                            • Subject
                                                                                            • Subscription
                                                                                            • Tape
                                                                                            • Thread
                                                                                            • Trap
                                                                                            • Udon
                                                                                            • Upgrade Proposal
                                                                                            • Userspace
                                                                                            • Vane
                                                                                            • Vase
                                                                                            • Vere
                                                                                            • Voting
                                                                                            • Warm atom
                                                                                            • Wet Gate
                                                                                            • Wing
                                                                                            • Wire
                                                                                            • Wrapper
                                                                                            • ~zod
                                                                                            • Zuse
                                                                                            • Additional

                                                                                              • Cryptography
                                                                                              • Mips (Maps of Maps)
                                                                                              • Software Distribution

                                                                                                • Overview
                                                                                                • Docket File
                                                                                                • Glob
                                                                                              Reference/Arvo/Eyre

                                                                                              Overview

                                                                                              Eyre is the webserver vane.

                                                                                              HTTP messages come in from outside and Eyre produces HTTP messages in response. In general, apps do not call Eyre; rather, Eyre calls apps. Eyre has a number of ways to handle such HTTP requests which we'll briefly describe.

                                                                                              Authentication

                                                                                              Most types of requests require the client provide a valid session cookie which is obtained by authenticating with your ship's web login code. Authentication is documented in the Authentication section of the External API Reference documentation.

                                                                                              The Channel System

                                                                                              Eyre's channel system is the primary way of interacting with Gall agents from outside of Urbit. It provides a simple JSON API that allows you to send data to apps and subscribe for updates from apps. Updates come back on a SSE (Server Sent Event) stream which you can easily handle with an EventSource object in Javascript or the equivalent in whichever language you prefer.

                                                                                              The channel system is designed to be extremely simple with just a handful of action and response JSON objects to deal. Essentially it's a thin layer on top of the underlying Gall agent interface. You can poke agents, subscribe for updates, etc, just like you would from within Urbit.

                                                                                              Detailed documentation of the channel system's JSON API is provided in the External API Reference document with corresponding examples in the Guide document.

                                                                                              Scrying

                                                                                              Along with the channel system, Eyre also provides a way to make read-only requests for data which are called scries. Eyre's scry interface is separate to the channel system but may be useful in conjunction with it.

                                                                                              Details of Eyre's scry API are in the Scry section of the External API Reference document.

                                                                                              Spider Threads

                                                                                              Spider (the Gall agent that manages threads) has an Eyre binding that allows you to run threads through Eyre. Spider's HTTP API is not part of Eyre proper, so is documented separately in the Threads documentation.

                                                                                              Generators

                                                                                              Generators, which are like Hoon scripts, can also be used through Eyre. Rather than having a predefined JSON API, they instead handle HTTP requests and return HTTP responses directly, and are therefore a more complex case that you're less likely to use.

                                                                                              Their usage is explained in the %serve section of the Internal API Reference documentation and a practical example is provided in the Generators section of the Guide document.

                                                                                              Direct HTTP Handling With Gall Agents

                                                                                              As well as the Channel System and Scries, it's also possible for Gall agents to deal directly with HTTP requests. This method is much more complicated than the channel system so you're unlikely to use it unless you want to build a custom HTTP-based API or something like that.

                                                                                              This method is explained in the %connect section of the Internal API Reference document and a detailed example is provided in the Agents: Direct HTTP section of the Guide document.

                                                                                              Cross-Origin Resource Sharing

                                                                                              Eyre supports both simple CORS requests and OPTIONS preflight requests. It has a CORS registry with three categories - approved, rejected and requests. Eyre will respond positively for origins in its approved list and negatively for all others. Eyre will add origins in requests that it doesn't have in either its approved or rejected lists to its requests list. Eyre always allows all methods and headers over CORS.

                                                                                              There are three generators - +cors-registry, |cors-approve, and |cors-reject to view, approve, and deny origins respectively from the dojo. Eyre also has tasks to approve and reject origins programmatically, and a number of scry endpoints to query them. Examples are also included in the Managing CORS Origins section of the Guide document.

                                                                                              Sections

                                                                                              External API Reference - Details of Eyre's external API including the channel system's JSON API.

                                                                                              Internal API Reference - The tasks Eyre takes and the gifts it returns.

                                                                                              Scry Reference - The scry endpoints of Eyre.

                                                                                              Data Types - Reference documentation of the various data types used by Eyre.

                                                                                              Guide - Practical examples of the different ways of using Eyre.

                                                                                              External API Reference

                                                                                              ->

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                                                                                              Last modified January 28, 2023