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-rw-r--r--guide/connect.md96
-rw-r--r--guide/http.md227
-rw-r--r--guide/introduction.md35
-rw-r--r--guide/protocols.md79
-rw-r--r--guide/toc.md11
-rw-r--r--guide/websocket.md85
6 files changed, 0 insertions, 533 deletions
diff --git a/guide/connect.md b/guide/connect.md
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-Connection
-==========
-
-This chapter describes how to open, monitor and close
-a connection using the Gun client.
-
-Opening a new connection
-------------------------
-
-Gun is designed with the SPDY and Websocket protocols in mind,
-and as such establishes a permanent connection to the remote
-server. Because of this, the connection must be initiated
-before being able to send any request.
-
-The process that creates the connection is also known as the
-owner of the connection, or the controlling process.. Only
-this process can perform operations on the connection, and
-only this process will receive messages from the connection.
-
-To open a new connection, the `gun:open/{2,3}` function can be used.
-
-``` erlang
-{ok, Pid} = gun:open("twitter.com", 443).
-```
-
-Gun will by default assume that SSL should be used.
-
-The connection is managed by a separate process and is supervised
-by the Gun supervisor directly.
-
-The connection can later be stopped either gracefully or abruptly
-by the client. If an unexpected disconnection occurs, the client
-will retry connecting every few seconds until it succeeds and
-can resume normal operations.
-
-Monitoring the connection process
----------------------------------
-
-The connection is managed by a separate process. Because
-software errors are a reality, it is important to monitor
-this process for failure. Thankfully, due to the asynchronous
-nature of Gun, we only need to create a monitor once when
-the connection is established.
-
-``` erlang
-{ok, Pid} = gun:open("twitter.com", 443).
-MRef = monitor(process, Pid).
-```
-
-There is no need to monitor again after that regardless of
-the number of requests sent or messages received.
-
-You can detect the process failure when receiving messages.
-
-``` erlang
-receive
- {'DOWN', Tag, _, _, Reason} ->
- error_logger:error_msg("Oops!"),
- exit(Reason);
- %% Receive Gun messages here...
-end.
-```
-
-You will probably want to reopen the connection when that
-happens.
-
-Closing the connection abruptly
--------------------------------
-
-The connection can be stopped abruptly at any time by calling
-the `gun:close/1` function.
-
-``` erlang
-gun:close(Pid).
-```
-
-The process is stopped immediately.
-
-Closing the connection gracefully
----------------------------------
-
-The connection can also be stopped gracefully by calling the
-`gun:shutdown/1` function.
-
-``` erlang
-gun:shutdown(Pid).
-```
-
-Gun will refuse any new requests from both the Erlang side and
-the server and will attempt to finish the currently opened
-streams. For example if you performed a GET request just before
-calling `gun:shutdown/1`, you will still receive the response
-before Gun closes the connection.
-
-If you set a monitor beforehand, it will inform you when the
-connection has finally been shutdown.
diff --git a/guide/http.md b/guide/http.md
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-Using HTTP
-==========
-
-This chapter describes how to use the Gun client for
-communicating with an HTTP or SPDY server.
-
-Streams
--------
-
-Every time a request is initiated, either by the client or the
-server, Gun creates a "stream". The stream controls whether
-the endpoints are still sending any data, and allows you to
-identify incoming messages.
-
-Streams are references in Gun, and are therefore always unique.
-
-Streams can be canceled at any time. This will stop any further
-messages being sent to the controlling process. Depending on
-its capabilities, the server will also be instructed to drop
-the request.
-
-Canceling a stream may result in Gun dropping the connection
-temporarily, to avoid uploading or downloading data that will
-not be used. This situation can only occur with HTTP, as SPDY
-features stream canceling as part of its protocol.
-
-To cancel a stream, the `gun:cancel/2` function can be used.
-
-``` erlang
-gun:cancel(Pid, StreamRef}.
-```
-
-Sending requests
-----------------
-
-Gun provides many convenient functions for performing common
-operations, like GET, POST or DELETE. It also provides a
-general purpose function in case you need other methods.
-
-The availability of these methods on the server can vary
-depending on the software used but also on a per-resource
-basis.
-
-To retrieve a resource, `gun:get/{2,3}` can be used. If you
-don't need the response body, `gun:head/{2,3}` is available.
-As this type of requests can't have a request body, only the
-path and optionally the headers can be specified.
-
-``` erlang
-%% Without headers.
-StreamRef = gun:get(Pid, "/organizations/extend").
-%% With headers.
-StreamRef = gun:get(Pid, "/organizations/extend", [
- {"accept", "application/json"},
- {"user-agent", "revolver/1.0"}]).
-```
-
-To create or update a resource, the functions `gun:patch/{3,4}`,
-`gun:post/{3,4}` and `gun:put/{3,4}` can be used. As this type
-of request is meant to come with a body, headers are not optional,
-because you must specify at least the content-type of the body,
-and if possible also the content-length. The body is however
-optional, because there might not be any at all, or because it
-will be subsequently streamed. If a body is set here it is assumed
-to be the full body.
-
-``` erlang
-%% Without body.
-StreamRef = gun:put(Pid, "/organizations/extend", [
- {"content-length", 23},
- {"content-type", "application/json"}]).
-%% With body.
-StreamRef = gun:put(Pid, "/organizations/extend", [
- {"content-length", 23},
- {"content-type", "application/json"}],
- "{\"msg\": \"Hello world!\"}").
-```
-
-To delete a resource, the `gun:delete/{2,3}` function can be
-used. It works similarly to the GET and HEAD functions.
-
-``` erlang
-%% Without headers.
-StreamRef = gun:delete(Pid, "/organizations/extend").
-%% With headers.
-StreamRef = gun:delete(Pid, "/organizations/extend", [
- {"accept", "application/json"},
- {"user-agent", "revolver/1.0"}]).
-```
-
-To obtain the functionality available for a given resource,
-the `gun:options/{2,3}` can be used. It also works like the
-GET and HEAD functions.
-
-``` erlang
-%% Without headers.
-StreamRef = gun:options(Pid, "/organizations/extend").
-%% With headers.
-StreamRef = gun:options(Pid, "/organizations/extend", [
- {"accept", "application/json"},
- {"user-agent", "revolver/1.0"}]).
-```
-
-You can obtain information about the server as a whole by
-using the special path `"*"`.
-
-``` erlang
-StreamRef = gun:options(Pid, "*").
-```
-
-Streaming data
---------------
-
-When a PATCH, POST or PUT operation is performed, and a
-content-type is specified but no body is given, Gun will
-expect data to be streamed to the connection using the
-`gun:data/4` function.
-
-This function can be called as many times as needed until
-all data is sent. The third argument needs to be `nofin`
-when there is remaining data to be sent, and `fin` for the
-last chunk. The last chunk may be empty if needed.
-
-For example, with an `IoDevice` opened like follow:
-
-``` erlang
-{ok, IoDevice} = file:open(Filepath, [read, binary, raw]).
-```
-
-The following function will stream all data until the end
-of the file:
-
-``` erlang
-sendfile(Pid, StreamRef, IoDevice) ->
- case file:read(IoDevice, 8000) of
- eof ->
- gun:data(Pid, StreamRef, fin, <<>>),
- file:close(IoDevice);
- {ok, Bin} ->
- gun:data(Pid, StreamRef, nofin, Bin),
- sendfile(Pid, StreamRef, IoDevice)
- end.
-```
-
-Receiving responses
--------------------
-
-All data received from the server is sent to the controlling
-process as a message. First a response message is sent, then
-zero or more data messages. If something goes wrong, error
-messages are sent instead.
-
-The response message will inform you whether there will be
-data messages following. If it contains `fin` then no data
-will follow. If it contains `nofin` then one or more data
-messages will arrive.
-
-When using SPDY this value is sent along the frame and simply
-passed on in the message. When using HTTP however Gun must
-guess whether data will follow by looking at the headers
-as documented in the HTTP RFC.
-
-``` erlang
-StreamRef = gun:get(Pid, "/"),
-receive
- {'DOWN', Tag, _, _, Reason} ->
- error_logger:error_msg("Oops!"),
- exit(Reason);
- {gun_response, Pid, StreamRef, fin, Status, Headers} ->
- no_data;
- {gun_response, Pid, StreamRef, nofin, Status, Headers} ->
- receive_data(Pid, StreamRef)
-after 1000 ->
- exit(timeout)
-end.
-```
-
-The `receive_data/2` function could look like this:
-
-``` erlang
-receive_data(Pid, Tag, StreamRef) ->
- receive
- {'DOWN', Tag, _, _, Reason} ->
- {error, incomplete};
- {gun_data, Pid, StreamRef, nofin, Data} ->
- io:format("~s~n", [Data]),
- receive_data(Pid, Tag, StreamRef);
- {gun_data, Pid, StreamRef, fin, Data} ->
- io:format("~s~n", [Data])
- after 1000 ->
- {error, timeout}
- end.
-```
-
-While it may seem verbose, using messages like this has the
-advantage of never locking your process, allowing you to
-easily debug your code. It also allows you to start more than
-one connection and concurrently perform queries on all of them
-at the same time.
-
-You may also use Gun in a synchronous manner by writing your
-own functions that perform a receive like demonstrated above.
-
-Dealing with server-pushed streams
-----------------------------------
-
-When using SPDY the server may decide to push extra resources
-after a request is performed. It will send a `gun_push` message
-which contains two references, one for the pushed stream, and
-one for the request this stream is associated with.
-
-Pushed streams typically feature a body. Replying to a pushed
-stream is forbidden and Gun will send an error message if
-attempted.
-
-Pushed streams can be received like this:
-
-``` erlang
-receive
- {gun_push, Pid, PushedStreamRef, StreamRef,
- Method, Host, Path, Headers} ->
- %% ...
-end
-```
-
-The pushed stream gets a new identifier but you still receive
-the `StreamRef` this stream is associated to.
diff --git a/guide/introduction.md b/guide/introduction.md
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-Introduction
-============
-
-Purpose
--------
-
-Gun is an asynchronous SPDY, HTTP and Websocket client.
-
-Prerequisites
--------------
-
-Knowledge of Erlang, but also of the HTTP, SPDY and Websocket
-protocols is required in order to read this guide.
-
-Supported platforms
--------------------
-
-Gun is tested and supported on Linux.
-
-Gun is developed for Erlang R16B+.
-
-Gun may be compiled on earlier Erlang versions with small source code
-modifications but there is no guarantee that it will work as expected.
-
-Conventions
------------
-
-In the HTTP protocol, the method name is case sensitive. All standard
-method names are uppercase.
-
-Header names are case insensitive. Gun converts all the header names
-to lowercase, and expects your application to provide lowercase header
-names also.
-
-The same applies to any other case insensitive value.
diff --git a/guide/protocols.md b/guide/protocols.md
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-Supported protocols
-===================
-
-This chapter describes the supported protocols and lists
-the calls that are valid for each of them.
-
-HTTP
-----
-
-HTTP is a text request-response protocol. The client
-initiates requests and then waits for the server responses.
-The server has no means of creating requests or pushing
-data to the client.
-
-SPDY
-----
-
-SPDY is a binary protocol based on HTTP, compatible with
-the HTTP semantics, that reduces the complexity of parsing
-requests and responses, compresses the HTTP headers and
-allows the server to push data directly to the client.
-
-Websocket
----------
-
-Websocket is a binary protocol established over HTTP that
-allows asynchronous concurrent communication between the
-client and the server. A Websocket server can push data to
-the client at any time.
-
-Websocket over SPDY is not supported by the Gun client at
-this time.
-
-Operations by protocol
-----------------------
-
-This table lists all Gun operations and whether they are
-compatible with the supported protocols.
-
-| Operation | SPDY | HTTP | Websocket |
-| ---------- | ---- | ---- | --------- |
-| delete | yes | yes | no |
-| get | yes | yes | no |
-| head | yes | yes | no |
-| options | yes | yes | no |
-| patch | yes | yes | no |
-| post | yes | yes | no |
-| put | yes | yes | no |
-| request | yes | yes | no |
-| response | yes | no | no |
-| data | yes | yes | no |
-| cancel | yes | yes | no |
-| ws_upgrade | no | yes | no |
-| ws_send | no | no | yes |
-
-While the `cancel` operation is available to HTTP, its effects
-will only be local, as there is no way to tell the server to
-stop sending data. Gun instead just doesn't forward the messages
-for this stream anymore.
-
-Messages by protocol
---------------------
-
-This table lists all messages that can be received depending
-on the current protocol.
-
-| Message | SPDY | HTTP | Websocket |
-| ------------------------------- | ---- | ---- | --------- |
-| {gun_push, ...} | yes | no | no |
-| {gun_response, ...} | yes | yes | no |
-| {gun_data, ...} | yes | yes | no |
-| {gun_error, _, StreamRef, _} | yes | yes | no |
-| {gun_error, _, _} | yes | yes | yes |
-| {gun_ws_upgrade, _, ok} | no | yes | no |
-| {gun_ws_upgrade, _, error, ...} | no | yes | no |
-| {gun_ws, ...} | no | no | yes |
-
-Do not forget that other messages may still be in the mailbox
-after you upgrade to Websocket.
diff --git a/guide/toc.md b/guide/toc.md
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-Gun User Guide
-==============
-
-The Gun User Guide explains in details how the Gun client
-should be used for communicating with Web servers.
-
- * [Introduction](introduction.md)
- * [Connection](connect.md)
- * [Supported protocols](protocols.md)
- * [Using HTTP](http.md)
- * [Using Websocket](websocket.md)
diff --git a/guide/websocket.md b/guide/websocket.md
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-Using Websocket
-===============
-
-This chapter describes how to use the Gun client for
-communicating with a Websocket server.
-
-HTTP upgrade
-------------
-
-Websocket is a protocol built on top of HTTP. To use Websocket,
-you must first request for the connection to be upgraded.
-
-Gun allows you to perform Websocket upgrade requests by using
-the `gun:ws_upgrade/{2,3}` function. Gun will fill out all
-necessary headers for performing the Websocket upgrade, but
-you can optionally specify additional headers, for example if
-you would like to setup a custom sub-protocol.
-
-``` erlang
-%% Without headers.
-gun:ws_upgrade(Pid, "/websocket").
-%% With headers.
-gun:ws_upgrade(Pid, "/websocket", [
- {"sec-websocket-protocol", "mychat"}
-]).
-```
-
-The success or failure of this operation will be sent as a
-message.
-
-``` erlang
-receive
- {gun_ws_upgrade, Pid, ok} ->
- upgrade_success(Pid);
- {gun_ws_upgrade, Pid, error, IsFin, Status, Headers} ->
- exit({ws_upgrade_failed, Status, Headers});
- %% More clauses here as needed.
-after 1000 ->
- exit(timeout);
-end.
-```
-
-Sending data
-------------
-
-You can then use the `gun:ws_send/2` function to send one or
-more frames to the server.
-
-``` erlang
-%% Send one text frame.
-gun:ws_send(Pid, {text, "Hello!"}).
-%% Send one text frame, one binary frame and close the connection.
-gun:ws_send(Pid, [
- {text, "Hello!"},
- {binary, SomeBin},
- close
-]).
-```
-
-Note that if you send a close frame, Gun will close the connection
-cleanly and will not attempt to reconnect afterwards, similar to
-calling `gun:shutdown/1`.
-
-Receiving data
---------------
-
-Every time Gun receives a frame from the server a message will be
-sent to the controlling process. This message will always contain
-a single frame.
-
-``` erlang
-receive
- {gun_ws, Pid, Frame} ->
- handle_frame(Pid, Frame);
- {gun_error, Pid, Reason} ->
- error_logger:error_msg("Oops! ~p~n", [Reason]),
- upgrade_again(Pid)
-end.
-```
-
-Gun will automatically send ping messages to the server to keep
-the connection alive, however if the connection dies and Gun has
-to reconnect it will not upgrade to Websocket automatically, you
-need to perform the operation when you receive the `gun_error`
-message.