Spider has an Eyre binding which allows threads to be run externally via authenticated HTTP POST requests.

Spider is bound to the /spider URL path, and expects the requested URL to look like:

http{s}://{host}/spider/{desk}/{inputMark}/{threadName}/{outputMark}

The desk is the desk in which the thread resides. The inputMark is the mark the thread takes. The threadName is the name of the thread, e.g. foo for /ted/foo/hoon. The outputMark is the mark the thread produces. You may also include a file extension though it doesn't have an effect.

When Spider receives an HTTP request, the following steps happen:

1. It converts the raw body of the message to json using de-json:html
2. It creates a tube:clay (mark conversion gate) from json to whatever input mark you've specified and does the conversion.
3. It runs the specified thread and provides a vase of (unit inputMark) as the argument.
4. The thread does its thing and finally produces its result as a vase of outputMark.
5. Spider creates another tube:clay from the output mark to json and converts it.
6. It converts the json back into raw data suitable for the HTTP response body using en-json:html.
7. Finally, it composes the HTTP response and passes it back to Eyre which passes it on to the client.

Thus, it's important to understand that the original HTTP request and final HTTP response must contain JSON data, and therefore the input & output marks you specify must each have a mark file in /mar that includes a conversion method for json -> inputMark and outputMark -> json respectively.

Example

Here we'll look at running Spider threads through Eyre.

Here's an extremely simple thread that takes a vase of (unit json) and just returns the json in a new vase. You can save it in /ted and |commit %base:

eyre-thread.hoon

/-  spider
=,  strand=strand:spider
^-  thread:spider
|=  arg=vase
=/  m  (strand ,vase)
^-  form:m
=/  =json
  (need !<((unit json) arg))
(pure:m !>(json))

First we must obtain a session cookie by authenticating.

Now we can try and run our thread. Spider is bound to the /spider URL path, and expects the rest of the path to be /{desk}/{inputMark}/{thread}/{outputMark}. Our {thread} is called eyre-thread and is in the %base {desk}. Both its {inputMark} and {outputMark} are json. Therefore, our URL path will be /spider/base/json/eyre-agent/json. Our request will be an HTTP POST request and the body will be some json, in this case [{"foo": "bar"}]:

curl -i --header "Content-Type: application/json" \
        --cookie "urbauth-~zod=0v6.h6t4q.2tkui.oeaqu.nihh9.i0qv6" \
        --request POST \
        --data '[{"foo": "bar"}]' \
        http://localhost:8080/spider/base/json/eyre-thread/json

Spider will run the thread and the result will be returned through Eyre in the body of an HTTP response with a 200 status code:

HTTP/1.1 200 ok
Date: Sun, 06 Jun 2021 05:32:45 GMT
Connection: keep-alive
Server: urbit/vere-1.5
set-cookie: urbauth-~zod=0v6.h6t4q.2tkui.oeaqu.nihh9.i0qv6; Path=/; Max-Age=604800
content-type: application/json
transfer-encoding: chunked

[{"foo":"bar"}]