[tarantool-patches] [PATCH v2] http: add CURLOPT_ACCEPT_ENCODING option

[Ilya Kosarev]

CURLOPT_ACCEPT_ENCODING option is now supported.
This option enables automatic decompression of HTTP downloads.
See https://curl.haxx.se/libcurl/c/CURLOPT_ACCEPT_ENCODING.html

Closes #4232

@TarantoolBot document
Title: http: CURLOPT_ACCEPT_ENCODING option
Update the documentation for curl options to reflect new
CURLOPT_ACCEPT_ENCODING option. It enables automatic
decompression of HTTP downloads by setting the contents of the
Accept-Encoding header sent in a HTTP request and enabling
decoding of a response when a Content-Encoding header is received.
This is a request, not an order; the server may or may not do it.
Servers might respond with Content-Encoding even without getting
an Accept-Encoding in the request. Servers might respond with a
different Content-Encoding than what was asked for in the request.
@param encoding specifies what encoding you'd like. This param
can be an empty string which means Accept-Encoding header will
contain all built-in supported encodings. This param can be
comma-separated list of accepted encodings, like:
"br, gzip, deflate". Bundled libcurl supports "identity",
meaning non-compressed, "deflate" which requests the server to
compress its response using the zlib algorithm and "gzip" which
requests the gzip algorithm. System libcurl also possibly
supports "br" which is brotli.
See https://curl.haxx.se/libcurl/c/CURLOPT_ACCEPT_ENCODING.html
---
https://github.com/tarantool/tarantool/tree/i.kosarev/gh-4232-curlopt-accept-encoding
https://github.com/tarantool/tarantool/issues/4232

Changes in v2:
- added docbot request
- fixed comments
- enhanced httpc_set_accept_encoding description
- fixed error handling for unsupported encodings

 src/httpc.c       | 22 +++++++++++++++++-----
 src/httpc.h       | 24 ++++++++++++++++++++++++
 src/lua/httpc.c   |  5 +++++
 src/lua/httpc.lua |  2 ++
 4 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/src/httpc.c b/src/httpc.c
index 8d18b9966..22b54d16a 100644
--- a/src/httpc.c
+++ b/src/httpc.c
@@ -361,6 +361,22 @@ httpc_set_follow_location(struct httpc_request *req, long follow)
 			 follow);
 }
 
+void
+httpc_set_accept_encoding(struct httpc_request *req, const char *encoding)
+{
+/*
+* CURLOPT_ACCEPT_ENCODING was called CURLOPT_ENCODING before
+* libcurl 7.21.6.
+*/
+#if LIBCURL_VERSION_NUM >= 0x071506
+	curl_easy_setopt(req->curl_request.easy, CURLOPT_ACCEPT_ENCODING,
+			 encoding);
+#else
+	curl_easy_setopt(req->curl_request.easy, CURLOPT_ENCODING,
+			 encoding);
+#endif
+}
+
 int
 httpc_execute(struct httpc_request *req, double timeout)
 {
@@ -429,16 +445,12 @@ httpc_execute(struct httpc_request *req, double timeout)
 	case CURLE_COULDNT_RESOLVE_PROXY:
 	case CURLE_COULDNT_RESOLVE_HOST:
 	case CURLE_COULDNT_CONNECT:
+	case CURLE_WRITE_ERROR:
 		/* 595 Connection Problem (AnyEvent non-standard) */
 		req->status = 595;
 		req->reason = curl_easy_strerror(req->curl_request.code);
 		++env->stat.failed_requests;
 		break;
-	case CURLE_WRITE_ERROR:
-		/* Diag is already set by curl_write_cb() */
-		assert(!diag_is_empty(&fiber()->diag));
-		++env->stat.failed_requests;
-		return -1;
 	case CURLE_OUT_OF_MEMORY:
 		diag_set(OutOfMemory, 0, "curl", "internal");
 		++env->stat.failed_requests;
diff --git a/src/httpc.h b/src/httpc.h
index 99fd8fbd4..f710b3d13 100644
--- a/src/httpc.h
+++ b/src/httpc.h
@@ -372,6 +372,30 @@ httpc_set_interface(struct httpc_request *req, const char *interface);
 void
 httpc_set_follow_location(struct httpc_request *req, long follow);
 
+/**
+ * Enable automatic decompression of HTTP downloads: set the
+ * contents of the Accept-Encoding header sent in a HTTP request
+ * and enable decoding of a response when a Content-Encoding
+ * header is received. This is a request, not an order; the
+ * server may or may not do it. Servers might respond with
+ * Content-Encoding even without getting an Accept-Encoding in the
+ * request. Servers might respond with a different
+ * Content-Encoding than what was asked for in the request.
+ * @param req request
+ * @param encoding - specify what encoding you'd like. This param
+ * can be an empty string which means Accept-Encoding header will
+ * contain all built-in supported encodings. This param can be
+ * comma-separated list of accepted encodings, like:
+ * "br, gzip, deflate". Bundled libcurl supports "identity",
+ * meaning non-compressed, "deflate" which requests the server to
+ * compress its response using the zlib algorithm and "gzip" which
+ * requests the gzip algorithm. System libcurl also possibly
+ * supports "br" which is brotli.
+ * @see https://curl.haxx.se/libcurl/c/CURLOPT_ACCEPT_ENCODING.html
+ */
+void
+httpc_set_accept_encoding(struct httpc_request *req, const char *encoding);
+
 /**
  * This function does async HTTP request
  * @param request - reference to request object with filled fields
diff --git a/src/lua/httpc.c b/src/lua/httpc.c
index a8e3e2525..6ed4eb788 100644
--- a/src/lua/httpc.c
+++ b/src/lua/httpc.c
@@ -315,6 +315,11 @@ luaT_httpc_request(lua_State *L)
 		httpc_set_follow_location(req, lua_toboolean(L, -1));
 	lua_pop(L, 1);
 
+	lua_getfield(L, 5, "accept_encoding");
+	if (!lua_isnil(L, -1))
+		httpc_set_accept_encoding(req, lua_tostring(L, -1));
+	lua_pop(L, 1);
+
 	if (httpc_execute(req, timeout) != 0) {
 		httpc_request_delete(req);
 		return luaT_error(L);
diff --git a/src/lua/httpc.lua b/src/lua/httpc.lua
index ce9bb9771..3224d8c10 100644
--- a/src/lua/httpc.lua
+++ b/src/lua/httpc.lua
@@ -296,6 +296,8 @@ end
 --          'Location' header that a server sends as part of an
 --          3xx response;
 --
+--      accept_encoding - enables automatic decompression of HTTP downloads;
+--
 --  Returns:
 --      {
 --          status=NUMBER,
-- 
2.17.1