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authorDavid Strauss <david@davidstrauss.net>2013-05-19 02:14:01 -0700
committerDaniel Stenberg <daniel@haxx.se>2013-05-19 11:19:28 +0200
commitce32176db749b40691c7fb08a1cb2ff184b4794e (patch)
tree5eab8bf73dcd557a922533fd64bdcba9eb126d9e
parent04f52e9b4db01bcbf672c9c69303a4e4ad0d0fb9 (diff)
xmlstream: XML stream parsing example source code
Add an XML stream parsing example using Expat. Add missing ignore for the binary from an unrelated example.
-rw-r--r--docs/examples/.gitignore2
-rw-r--r--docs/examples/README1
-rw-r--r--docs/examples/xmlstream.c158
3 files changed, 161 insertions, 0 deletions
diff --git a/docs/examples/.gitignore b/docs/examples/.gitignore
index cbe0d04d4..40bd837b8 100644
--- a/docs/examples/.gitignore
+++ b/docs/examples/.gitignore
@@ -43,3 +43,5 @@ simplessl
smtp-multi
smtp-tls
url2file
+usercertinmem
+xmlstream
diff --git a/docs/examples/README b/docs/examples/README
index b89338f62..1ca62a154 100644
--- a/docs/examples/README
+++ b/docs/examples/README
@@ -78,4 +78,5 @@ simplepost.c - HTTP POST
simplessl.c - HTTPS example with certificates many options set
synctime.c - Sync local time by extracting date from remote HTTP servers
url2file.c - download a document and store it in a file
+xmlstream.c - Stream-parse a document using the streaming Expat parser
10-at-a-time.c - Download many files simultaneously, 10 at a time.
diff --git a/docs/examples/xmlstream.c b/docs/examples/xmlstream.c
new file mode 100644
index 000000000..4d67f98eb
--- /dev/null
+++ b/docs/examples/xmlstream.c
@@ -0,0 +1,158 @@
+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+/* Stream-parse a document using the streaming Expat parser.
+ * Written by David Strauss
+ *
+ * Expat => http://www.libexpat.org/
+ *
+ * gcc -Wall -I/usr/local/include xmlstream.c -lcurl -lexpat -o xmlstream
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <expat.h>
+#include <curl/curl.h>
+
+struct MemoryStruct {
+ char *memory;
+ size_t size;
+};
+
+struct ParserStruct {
+ int ok;
+ size_t tags;
+ size_t depth;
+ struct MemoryStruct characters;
+};
+
+static void startElement(void *userData, const XML_Char *name, const XML_Char **atts)
+{
+ struct ParserStruct *state = (struct ParserStruct *) userData;
+ state->tags++;
+ state->depth++;
+
+ /* Get a clean slate for reading in character data. */
+ free(state->characters.memory);
+ state->characters.memory = NULL;
+ state->characters.size = 0;
+}
+
+static void characterDataHandler(void *userData, const XML_Char *s, int len)
+{
+ struct ParserStruct *state = (struct ParserStruct *) userData;
+ struct MemoryStruct *mem = &state->characters;
+
+ mem->memory = realloc(mem->memory, mem->size + len + 1);
+ if(mem->memory == NULL) {
+ /* Out of memory. */
+ fprintf(stderr, "Not enough memory (realloc returned NULL).\n");
+ state->ok = 0;
+ return;
+ }
+
+ memcpy(&(mem->memory[mem->size]), s, len);
+ mem->size += len;
+ mem->memory[mem->size] = 0;
+}
+
+static void endElement(void *userData, const XML_Char *name)
+{
+ struct ParserStruct *state = (struct ParserStruct *) userData;
+ state->depth--;
+
+ printf("%5lu %10lu %s\n", state->depth, state->characters.size, name);
+}
+
+static size_t parseStreamCallback(void *contents, size_t length, size_t nmemb, void *userp)
+{
+ XML_Parser parser = (XML_Parser) userp;
+ size_t real_size = length * nmemb;
+ struct ParserStruct *state = (struct ParserStruct *) XML_GetUserData(parser);
+
+ /* Only parse if we're not already in a failure state. */
+ if (state->ok && XML_Parse(parser, contents, real_size, 0) == 0) {
+ int error_code = XML_GetErrorCode(parser);
+ fprintf(stderr, "Parsing response buffer of length %lu failed with error code %d (%s).\n",
+ real_size, error_code, XML_ErrorString(error_code));
+ state->ok = 0;
+ }
+
+ return real_size;
+}
+
+int main(void)
+{
+ CURL *curl_handle;
+ CURLcode res;
+ XML_Parser parser;
+ struct ParserStruct state;
+
+ /* Initialize the state structure for parsing. */
+ memset(&state, 0, sizeof(struct ParserStruct));
+ state.ok = 1;
+
+ /* Initialize a namespace-aware parser. */
+ parser = XML_ParserCreateNS(NULL, '\0');
+ XML_SetUserData(parser, &state);
+ XML_SetElementHandler(parser, startElement, endElement);
+ XML_SetCharacterDataHandler(parser, characterDataHandler);
+
+ /* Initalize a libcurl handle. */
+ curl_global_init(CURL_GLOBAL_ALL ^ CURL_GLOBAL_SSL);
+ curl_handle = curl_easy_init();
+ curl_easy_setopt(curl_handle, CURLOPT_URL, "http://www.w3schools.com/xml/simple.xml");
+ curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, parseStreamCallback);
+ curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)parser);
+
+ printf("Depth Characters Closing Tag\n");
+
+ /* Perform the request and any follow-up parsing. */
+ res = curl_easy_perform(curl_handle);
+ if(res != CURLE_OK) {
+ fprintf(stderr, "curl_easy_perform() failed: %s\n",
+ curl_easy_strerror(res));
+ }
+ else if (state.ok) {
+ /* Expat requires one final call to finalize parsing. */
+ if (XML_Parse(parser, NULL, 0, 1) == 0) {
+ int error_code = XML_GetErrorCode(parser);
+ fprintf(stderr, "Finalizing parsing failed with error code %d (%s).\n",
+ error_code, XML_ErrorString(error_code));
+ }
+ else {
+ printf(" --------------\n");
+ printf(" %lu tags total\n", state.tags);
+ }
+ }
+
+ /* Clean up. */
+ free(state.characters.memory);
+ XML_ParserFree(parser);
+ curl_easy_cleanup(curl_handle);
+ curl_global_cleanup();
+
+ return 0;
+}