diff options
Diffstat (limited to 'doc/src/guide/migrating_from_2.0.asciidoc')
| -rw-r--r-- | doc/src/guide/migrating_from_2.0.asciidoc | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/doc/src/guide/migrating_from_2.0.asciidoc b/doc/src/guide/migrating_from_2.0.asciidoc new file mode 100644 index 0000000..c76430c --- /dev/null +++ b/doc/src/guide/migrating_from_2.0.asciidoc @@ -0,0 +1,107 @@ +[appendix] +== Migrating from Cowboy 2.0 to 2.1 + +Cowboy 2.1 focused on adding features that were temporarily +removed in Cowboy 2.0. A number of bugs found in the 2.0 +release were also fixed. + +=== Features added + +* It is now possible to obtain the client TLS certificate + and the local IP/port for the connection from the Req object. + +* Informational responses (1XX responses) can now be sent. + They must be sent before initiating the final response. + +* The `expect: 100-continue` header is now handled + automatically. The 100 response will be sent on the + first `cowboy_req:read_body/2,3,4` call. This only applies + when using the default `cowboy_stream_h` stream handler. + +=== Experimental features added + +Experimental features are previews of features that will be +added in a future release. They are not documented and their +interface may change at any time. You are welcome to try them +and provide feedback. + +* The `cowboy_metrics_h` stream handler can be used to + extract metrics out of Cowboy. It must be used first in + the list of stream handlers, and will record all events + related to requests, responses and spawned processes. + When the stream terminates it will pass this information + to a user-defined callback. + +* The `cowboy_tracer_h` stream handler can be used to setup + automatic tracing of specific requests. You can conditionally + enable tracing based on a function, header, path or any other + element from the request and the trace will apply to the + entire connection and any processes created by it. This is + meant to be used for debugging both in tests and production. + +=== Changed behaviors + +* The `cowboy_rest` handler now implements a mechanism for + switching to a different type of handler from any callback + where `stop` is also allowed. Switch by returning + `{switch_handler, Module}` or `{switch_handler, Module, Opts}`. + This is especially useful for switching to `cowboy_loop` + for streaming the request or response body. + +* REST callbacks that do not allow `stop` as a return value + are now explicitly listed in the documentation. + +=== New functions + +* The function `cowboy_req:sock/1` returns the IP/port + of the local socket. + +* The function `cowboy_req:cert/1` returns the client + TLS certificate or `undefined` if it isn't available. + +* The function `cowboy_req:inform/2,3` sends an + informational response. + +=== Bugs fixed + +* Ensure HTTP/2 connections are not closed prematurely + when the user code does not read the request body. + +* Ensure HTTP/1.1 streams are not terminated too early. + Their behavior is now consistent with the HTTP/2 code + where the stream handler is only terminated when the + `stop` command is returned. + +* Sending zero-sized data from stream handlers or from + `cowboy_req:stream_body/3` could lead to issues with + HTTP/1.1. This has been fixed. + +* The final chunk sent by Cowboy when it terminates a + chunked body after the handler process exits was not + passed through stream handlers, which could lead to + issues when `cowboy_compress_h` was being used. This + is now corrected. + +* The stream handler state was discarded in some cases + where Cowboy had to send a response or response data + automatically when ending a stream. This has now + been corrected. + +* The stream handler callback `terminate/3` will now be + called when switching to another protocol using the + command `switch_protocol`. This doesn't apply when + doing upgrades to HTTP/2 as those occur before the + stream is initialized. + +* Cowlib has been updated to 2.0.1 to fix an issue with + Websocket compression when using Erlang/OTP 20.1. Note + that at the time of writing all 20.1 versions (from + 20.1 to 20.1.4) have issues when compression is enabled. + It is expected to work properly from 20.1.5 onward. In + the meantime it is recommended to run the plain 20.1 + release and disable Websocket compression, or use a + release before 20.1. + +* Cowboy will no longer crash when the `cowboy_clock` + process is not running. This can happen when Cowboy + is being restarted during upgrades, for example. |