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authorChristian Grothoff <christian@grothoff.org>2019-11-23 10:48:05 +0100
committerChristian Grothoff <christian@grothoff.org>2019-11-23 10:48:05 +0100
commita2a5f429159a5be2a453dcc7dacf30e7c0f9e963 (patch)
treed056233d3b81b6baf4c05b4573568eab99b8fbf4 /src/mhd
parent161b801fd691e0db697f2228dd96c87f71d01f40 (diff)
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start with libtalermhd
Diffstat (limited to 'src/mhd')
-rw-r--r--src/mhd/Makefile.am24
-rw-r--r--src/mhd/mhd_responses.c319
2 files changed, 343 insertions, 0 deletions
diff --git a/src/mhd/Makefile.am b/src/mhd/Makefile.am
new file mode 100644
index 00000000..2c6d464f
--- /dev/null
+++ b/src/mhd/Makefile.am
@@ -0,0 +1,24 @@
+# This Makefile.am is in the public domain
+AM_CPPFLAGS = -I$(top_srcdir)/src/include
+
+if USE_COVERAGE
+ AM_CFLAGS = --coverage -O0
+ XLIB = -lgcov
+endif
+
+lib_LTLIBRARIES = \
+ libtalermhd.la
+
+libtalermhd_la_SOURCES = \
+ mhd_responses.c
+libtalermhd_la_LDFLAGS = \
+ -version-info 0:0:0 \
+ -export-dynamic -no-undefined
+libtalermhd_la_LIBADD = \
+ -lgnunetjson \
+ $(top_builddir)/src/json/libtalerjson.la \
+ $(top_builddir)/src/util/libtalerutil.la \
+ -lgnunetutil \
+ -ljansson \
+ $(XLIB)
+
diff --git a/src/mhd/mhd_responses.c b/src/mhd/mhd_responses.c
new file mode 100644
index 00000000..24d55bfa
--- /dev/null
+++ b/src/mhd/mhd_responses.c
@@ -0,0 +1,319 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2014-2019 Taler Systems SA
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU Affero General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License along with
+ TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file mhd_responses.c
+ * @brief API for generating HTTP replies
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <zlib.h>
+#include "taler_util.h"
+#include "taler_mhd_lib.h"
+
+
+/**
+ * Enable checking signatures before we hand them out
+ * (even though we should have checked them before).
+ * So technically these checks are redundant, but good
+ * during testing.
+ */
+#define SANITY_CHECKS_ON 1
+
+
+/**
+ * Global options for response generation.
+ */
+static enum TALER_MHD_GlobalOptions TM_go;
+
+
+/**
+ * Set global options for response generation
+ * within libtalermhd.
+ *
+ * @param go global options to use
+ */
+void
+TALER_MHD_setup (enum TALER_MHD_GlobalOptions go)
+{
+ TM_go = go;
+}
+
+
+/**
+ * Add headers we want to return in every response.
+ * Useful for testing, like if we want to always close
+ * connections.
+ *
+ * @param response response to modify
+ */
+void
+TALER_MHD_add_global_headers (struct MHD_Response *response)
+{
+ if (0 != (TM_go & TALER_MHD_GO_FORCE_CONNECTION_CLOSE))
+ GNUNET_break (MHD_YES ==
+ MHD_add_response_header (response,
+ MHD_HTTP_HEADER_CONNECTION,
+ "close"));
+}
+
+
+/**
+ * Is HTTP body deflate compression supported by the client?
+ *
+ * @param connection connection to check
+ * @return #MHD_YES if 'deflate' compression is allowed
+ *
+ * Note that right now we're ignoring q-values, which is technically
+ * not correct, and also do not support "*" anywhere but in a line by
+ * itself. This should eventually be fixed, see also
+ * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
+ */
+int
+TALER_MHD_can_compress (struct MHD_Connection *connection)
+{
+ const char *ae;
+ const char *de;
+
+ if (0 != (TM_go & TALER_MHD_GO_DISABLE_COMPRESSION))
+ return MHD_NO;
+ ae = MHD_lookup_connection_value (connection,
+ MHD_HEADER_KIND,
+ MHD_HTTP_HEADER_ACCEPT_ENCODING);
+ if (NULL == ae)
+ return MHD_NO;
+ if (0 == strcmp (ae,
+ "*"))
+ return MHD_YES;
+ de = strstr (ae,
+ "deflate");
+ if (NULL == de)
+ return MHD_NO;
+ if ( ( (de == ae) ||
+ (de[-1] == ',') ||
+ (de[-1] == ' ') ) &&
+ ( (de[strlen ("deflate")] == '\0') ||
+ (de[strlen ("deflate")] == ',') ||
+ (de[strlen ("deflate")] == ';') ) )
+ return MHD_YES;
+ return MHD_NO;
+}
+
+
+/**
+ * Try to compress a response body. Updates @a buf and @a buf_size.
+ *
+ * @param[in,out] buf pointer to body to compress
+ * @param[in,out] buf_size pointer to initial size of @a buf
+ * @return #MHD_YES if @a buf was compressed
+ */
+int
+TALER_MHD_body_compress (void **buf,
+ size_t *buf_size)
+{
+ Bytef *cbuf;
+ uLongf cbuf_size;
+ int ret;
+
+ cbuf_size = compressBound (*buf_size);
+ cbuf = malloc (cbuf_size);
+ if (NULL == cbuf)
+ return MHD_NO;
+ ret = compress (cbuf,
+ &cbuf_size,
+ (const Bytef *) *buf,
+ *buf_size);
+ if ( (Z_OK != ret) ||
+ (cbuf_size >= *buf_size) )
+ {
+ /* compression failed */
+ free (cbuf);
+ return MHD_NO;
+ }
+ free (*buf);
+ *buf = (void *) cbuf;
+ *buf_size = (size_t) cbuf_size;
+ return MHD_YES;
+}
+
+
+/**
+ * Send JSON object as response.
+ *
+ * @param connection the MHD connection
+ * @param json the json object
+ * @param response_code the http response code
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json (struct MHD_Connection *connection,
+ const json_t *json,
+ unsigned int response_code)
+{
+ struct MHD_Response *resp;
+ void *json_str;
+ size_t json_len;
+ int ret;
+ int comp;
+
+ json_str = json_dumps (json,
+ JSON_INDENT (2));
+ if (NULL == json_str)
+ {
+ /**
+ * This log helps to figure out which
+ * function called this one and assert-failed.
+ */
+ TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
+ response_code);
+
+ GNUNET_assert (0);
+ return MHD_NO;
+ }
+ json_len = strlen (json_str);
+ /* try to compress the body */
+ comp = MHD_NO;
+ if (MHD_YES ==
+ TALER_MHD_can_compress (connection))
+ comp = TALER_MHD_body_compress (&json_str,
+ &json_len);
+ resp = MHD_create_response_from_buffer (json_len,
+ json_str,
+ MHD_RESPMEM_MUST_FREE);
+ if (NULL == resp)
+ {
+ free (json_str);
+ GNUNET_break (0);
+ return MHD_NO;
+ }
+ TALER_MHD_add_global_headers (resp);
+ GNUNET_break (MHD_YES ==
+ MHD_add_response_header (resp,
+ MHD_HTTP_HEADER_CONTENT_TYPE,
+ "application/json"));
+ if (MHD_YES == comp)
+ {
+ /* Need to indicate to client that body is compressed */
+ if (MHD_NO ==
+ MHD_add_response_header (resp,
+ MHD_HTTP_HEADER_CONTENT_ENCODING,
+ "deflate"))
+ {
+ GNUNET_break (0);
+ MHD_destroy_response (resp);
+ return MHD_NO;
+ }
+ }
+ ret = MHD_queue_response (connection,
+ response_code,
+ resp);
+ MHD_destroy_response (resp);
+ return ret;
+}
+
+
+/**
+ * Function to call to handle the request by building a JSON
+ * reply from a format string and varargs.
+ *
+ * @param connection the MHD connection to handle
+ * @param response_code HTTP response code to use
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
+ unsigned int response_code,
+ const char *fmt,
+ ...)
+{
+ json_t *json;
+ va_list argp;
+ int ret;
+ json_error_t jerror;
+
+ va_start (argp, fmt);
+ json = json_vpack_ex (&jerror, 0, fmt, argp);
+ va_end (argp);
+ if (NULL == json)
+ {
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Failed to pack JSON with format `%s': %s\n",
+ fmt,
+ jerror.text);
+ GNUNET_break (0);
+ return MHD_NO;
+ }
+ ret = TALER_MHD_reply_json (connection,
+ json,
+ response_code);
+ json_decref (json);
+ return ret;
+}
+
+
+/**
+ * Send a response indicating an error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param http_status HTTP status code to use
+ * @param hint human readable hint about the error
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_with_error (struct MHD_Connection *connection,
+ unsigned int http_status,
+ enum TALER_ErrorCode ec,
+ const char *hint)
+{
+ return TALER_MHD_reply_json_pack (connection,
+ http_status,
+ "{s:I, s:s}",
+ "code", (json_int_t) ec,
+ "hint", hint);
+}
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_request_too_large (struct MHD_Connection *connection)
+{
+ struct MHD_Response *resp;
+ int ret;
+
+ resp = MHD_create_response_from_buffer (0,
+ NULL,
+ MHD_RESPMEM_PERSISTENT);
+ if (NULL == resp)
+ return MHD_NO;
+ TALER_MHD_add_global_headers (resp);
+ ret = MHD_queue_response (connection,
+ MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
+ resp);
+ MHD_destroy_response (resp);
+ return ret;
+}
+
+
+/* end of mhd_responses.c */