HTTP

HTTP client and server functionality for Julia

Documentation	Build Status

Installation

The package can be installed with Julia's package manager, either by using the Pkg REPL mode (press ] to enter):

pkg> add HTTP

or by using Pkg functions

julia> using Pkg; Pkg.add("HTTP")

Project Status

The package has matured and is used in many production systems. But as with all open-source software, please try it out and report your experience.

The package is tested against Julia 1.0, 1.3 & current master on Linux, macOS, and Windows.

Contributing and Questions

Contributions are very welcome, as are feature requests and suggestions. Please open an issue if you encounter any problems or would just like to ask a question.

Client Examples

HTTP.request sends a HTTP Request Message and returns a Response Message.

r = HTTP.request("GET", "http://httpbin.org/ip"; verbose=3)
println(r.status)
println(String(r.body))

HTTP.open sends a HTTP Request Message and opens an IO stream from which the Response can be read.

HTTP.open(:GET, "https://tinyurl.com/bach-cello-suite-1-ogg") do http
    open(`vlc -q --play-and-exit --intf dummy -`, "w") do vlc
        write(vlc, http)
    end
end

Server Examples

HTTP.Servers.listen:

The server will start listening on 127.0.0.1:8081 by default.

using HTTP

HTTP.listen() do http::HTTP.Stream
    @show http.message
    @show HTTP.header(http, "Content-Type")
    while !eof(http)
        println("body data: ", String(readavailable(http)))
    end
    HTTP.setstatus(http, 404)
    HTTP.setheader(http, "Foo-Header" => "bar")
    HTTP.startwrite(http)
    write(http, "response body")
    write(http, "more response body")
end

HTTP.Handlers.serve:

using HTTP

HTTP.serve() do request::HTTP.Request
   @show request
   @show request.method
   @show HTTP.header(request, "Content-Type")
   @show HTTP.payload(request)
   try
       return HTTP.Response("Hello")
   catch e
       return HTTP.Response(404, "Error: $e")
   end
end

WebSocket Examples

julia> @async HTTP.WebSockets.listen("127.0.0.1", UInt16(8081)) do ws
           while !eof(ws)
               data = readavailable(ws)
               write(ws, data)
           end
       end

julia> HTTP.WebSockets.open("ws://127.0.0.1:8081") do ws
           write(ws, "Hello")
           x = readavailable(ws)
           @show x
           println(String(x))
       end;
x = UInt8[0x48, 0x65, 0x6c, 0x6c, 0x6f]
Hello

Custom HTTP Layer Examples

Notes:

• There is no enforcement of a "well-defined" stack, you can insert a layer anywhere in the stack even if it logically does not make sense
• When creating a custom layer, you need to create a request(), see below for an example
• Custom layers is only implemented with the "low-level" request() calls, not the "convenience" functions such as HTTP.get(), HTTP.put(), etc.

julia> module TestRequest
               import HTTP: Layer, request, Response

               abstract type TestLayer{Next <: Layer} <: Layer{Next} end
               export TestLayer, request

               function request(::Type{TestLayer{Next}}, io::IO, req, body; kw...)::Response where Next
                       println("Insert your custom layer logic here!")
                       return request(Next, io, req, body; kw...)
               end
       end

julia> using HTTP
julia> using ..TestRequest

julia> custom_stack = insert(stack(), StreamLayer, TestLayer)

julia> result = request(custom_stack, "GET", "https://httpbin.org/ip")

Insert your custom layer logic here!
HTTP.Messages.Response:
"""
HTTP/1.1 200 OK
Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: *
Content-Type: application/json
Date: Fri, 30 Aug 2019 14:13:17 GMT
Referrer-Policy: no-referrer-when-downgrade
Server: nginx
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-XSS-Protection: 1; mode=block
Content-Length: 45
Connection: keep-alive

{
  "origin": "--Redacted--"
}
"""

julia>