Add example of REST client
by using libcurl for HTTP connection and M*LIB for JSON formating.
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Patrick Pelissier committed
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@@ -31,7 +31,7 @@ RM=rm -f
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.SUFFIXES: .c .exe
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.c.exe:
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$(CC) $(CFLAGS) $(CPPFLAGS) $< -o $@ `cat config` $(LDFLAGS)
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$(CC) $(CFLAGS) $(CPPFLAGS) $< -o $@ `cat config` `cat config.curl` $(LDFLAGS)
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.c.o:
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@$(MAKE) config
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@@ -53,11 +53,11 @@ config:
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$(CC) $(CFLAGS) $(CPPFLAGS) -I$(GMP_DIR)/include -L$(GMP_DIR)/lib config-test.c -lgmp -o config-test.exe $(LDFLAGS) 2> /dev/null && echo "-DHAVE_GMP=1 -DHAVE_MPFR=0 -I$(GMP_DIR)/include -L$(GMP_DIR)/lib -lgmp" > config || echo "-DHAVE_GMP=0 -DHAVE_MPFR=0 " > config
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printf "#include <mpfr.h>\nint main(void){mpfr_t z; mpfr_init(z); return 0;}\n" > config-test.c
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$(CC) $(CFLAGS) $(CPPFLAGS) -I$(GMP_DIR)/include -I$(MPFR_DIR)/include -L$(GMP_DIR)/lib -L$(MPFR_DIR)/lib config-test.c -lmpfr -lgmp -o config-test.exe $(LDFLAGS) 2> /dev/null && echo "-DHAVE_GMP=1 -DHAVE_MPFR=1 -I$(GMP_DIR)/include -L$(GMP_DIR)/lib -I$(MPFR_DIR)/include -L$(MPFR_DIR)/lib -lmpfr -lgmp" > config || echo "MPFR not available"
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printf "#include <curl/curl.h>\nint main(void){curl_global_init(CURL_GLOBAL_DEFAULT);}" > config-test.c
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$(CC) $(CFLAGS) $(CPPFLAGS) config-test.c `curl-config --cflags --libs` -o config-test.exe 2> /dev/null && echo "-DHAVE_CURL=1 `curl-config --cflags --libs`" > config.curl || echo "-DHAVE_CURL=0 " > config.curl
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printf "#include <stdio.h>\nint main(void){printf(\"Ok\"); return 0;}\n" > config-test.c
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$(CC) $(CFLAGS) $(CPPFLAGS) config-test.c -ffunction-sections -fdata-sections -Wl,--gc-sections 2> /dev/null && echo "-ffunction-sections -fdata-sections -Wl,--gc-sections" > config.link || echo "" > config.link
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$(RM) config-test.c config-test.exe
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clean:
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$(RM) *.exe *.s *~ *.o ./a.dat config config.link
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$(RM) *.exe *.s *~ *.o ./a.dat config config.link config.curl
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@@ -0,0 +1,160 @@
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#if HAVE_CURL
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#include <curl/curl.h>
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#include "m-dict.h"
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#include "m-tuple.h"
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#include "m-string.h"
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#include "m-list.h"
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#include "m-serial-json.h"
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/////////////////////////////////////////
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// Define container types
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// First a generic map string to string
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DICT_DEF2(map_str, string_t, string_t)
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#define M_OPL_map_str_t() DICT_OPLIST(map_str, STRING_OPLIST, STRING_OPLIST)
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// This structure matches the JSON structure returns by the used WEB server
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// for the GET command.
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// It can be whatever you want provided it matches what is expected by the WEB server
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TUPLE_DEF2(web_data,
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(args, map_str_t),
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(headers, map_str_t),
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(origin, string_t),
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(url, string_t))
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#define M_OPL_web_data_t() TUPLE_OPLIST(web_data, M_OPL_map_str_t(), M_OPL_map_str_t(), STRING_T, STRING_T)
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/////////////////////////////////////////
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static size_t
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write_data(void *buffer, size_t size, size_t nmemb, void *userp)
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{
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(void) size; // Parameter not used
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char *src = buffer;
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string_ptr str = userp;
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for(size_t i = 0; i < nmemb; i++) {
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string_push_back(str, src[i]);
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}
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return nmemb;
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}
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static bool get_data(web_data_t data, const char url[])
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{
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m_serial_return_code_t r = M_SERIAL_FAIL;
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CURLcode res;
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string_t str;
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CURL *handle = curl_easy_init();
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if (handle) {
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string_init(str);
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// Perform an http GET request and fill in str with the JSON answer
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curl_easy_setopt(handle, CURLOPT_URL, url);
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curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, write_data);
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curl_easy_setopt(handle, CURLOPT_WRITEDATA, str);
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res = curl_easy_perform(handle);
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curl_easy_cleanup(handle);
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if (res == CURLE_OK) {
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// Parse the string and fill in the object
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m_serial_str_json_read_t serial;
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m_serial_str_json_read_init(serial, string_get_cstr(str));
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r = web_data_in_serial(data, serial);
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m_serial_str_json_read_clear(serial);
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}
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string_clear(str);
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}
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return r == M_SERIAL_OK_DONE;
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}
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/////////////////////////////////////////
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static size_t
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ignore_data(void *buffer, size_t size, size_t nmemb, void *userp)
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{
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(void) buffer; // Parameter not used
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(void) size; // Parameter not used
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(void) userp; // Parameter not used
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return nmemb;
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}
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static bool post_data(web_data_t data, const char url[], bool display_answer)
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{
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m_serial_return_code_t r = M_SERIAL_FAIL;
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CURLcode res = 0;
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string_t str;
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CURL *handle = curl_easy_init();
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if (handle) {
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string_init(str);
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// Get a JSON string
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m_serial_str_json_write_t serial;
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m_serial_str_json_write_init(serial, str);
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r = web_data_out_serial(serial, data);
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m_serial_str_json_write_clear(serial);
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if (r == M_SERIAL_OK_DONE) {
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// Post JSON string
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struct curl_slist *headers=NULL;
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headers = curl_slist_append(headers, "Content-Type: text/json");
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if (headers != NULL) {
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curl_easy_setopt(handle, CURLOPT_POSTFIELDS, string_get_cstr(str));
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curl_easy_setopt(handle, CURLOPT_URL, url);
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curl_easy_setopt(handle, CURLOPT_HTTPHEADER, headers);
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if (display_answer == false) {
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curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, ignore_data);
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curl_easy_setopt(handle, CURLOPT_WRITEDATA, NULL);
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}
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res = curl_easy_perform(handle);
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curl_slist_free_all(headers);
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}
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}
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curl_easy_cleanup(handle);
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string_clear(str);
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}
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return (r == M_SERIAL_OK_DONE) && (res == CURLE_OK);
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}
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/////////////////////////////////////////
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// Remote server URL
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#define URL_GET "https://httpbin.org/get"
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#define URL_POST "https://httpbin.org/post"
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int main(void)
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{
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CURLcode ret = curl_global_init(CURL_GLOBAL_DEFAULT);
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if (ret != CURLE_OK) abort();
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web_data_t data;
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web_data_init(data);
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// Test http GET
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bool b = get_data(data, URL_GET);
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if (b) {
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// We success receiving the JSON object and fill in the C object web_data with it.
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// Let's display the object content:
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printf("SUCCESS. Receive data =\n");
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web_data_out_str(stdout, data);
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printf("\n");
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} else {
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printf("ERROR: Cannot GET data or get data are not in expected format\n");
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}
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// Test http POST
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web_data_emplace_origin(data, "This is the origin");
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web_data_emplace_url(data, "This is the URL");
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//web_data_set_origin(data, STRING_CTE("This is the origin"));
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//web_data_set_url(data, STRING_CTE("This is the URL"));
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b = post_data(data, URL_POST, false);
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if (b) {
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printf("SUCCESS: Post\n");
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} else {
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printf("ERROR post\n");
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}
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web_data_clear(data);
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curl_global_cleanup();
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return 0;
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}
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#else
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int main(void) { return 0; }
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#endif
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