最近在学习libcurl，并利用它提交POST请求，可是返回的响应总是无从验证该次POST请求是否成功提交了。
1. 先看下根据firebug提交的一次成功的请求，这里以login我喜欢上的xiami为例，嘻嘻~
1.1 本次POST请求的HTTP交互
1.2 POST
1.3 经server端redirect的GET
2. OK，接下来看下使用libcurl向xiami发送POST请求
2.1 使用libcurl的大概流程
curl_easy_init()
curl_easy_setopt()
curl_easy_perform()
curl_easy_cleanup()
呵呵~超简单的吧，具体的意思这里就不详细说了，参见http://curl.haxx.se/libcurl/c/
2.2 再来看简单的代码
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <curl/curl.h>
- #define POSTURL "http://www.xiami.com/member/login"
- #define POSTFIELDS "email=myemail@163.com&password=mypassword&autologin=1&submit=登 录&type="
- #define FILENAME "curlposttest.log"
- size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp);
- int main(int argc, char *argv[]) {
- CURL *curl;
- CURLcode res;
- FILE *fptr;
- struct curl_slist *http_header = NULL;
- if ((fptr = fopen(FILENAME, "w")) == NULL) {
- fprintf(stderr, "fopen file error: %s\n", FILENAME);
- exit(1);
- }
- curl = curl_easy_init();
- curl_easy_setopt(curl, CURLOPT_URL, POSTURL);
- curl_easy_setopt(curl, CURLOPT_POSTFIELDS, POSTFIELDS);
- curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
- curl_easy_setopt(curl, CURLOPT_WRITEDATA, fptr);
- curl_easy_setopt(curl, CURLOPT_POST, 1);
- curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
- curl_easy_setopt(curl, CURLOPT_HEADER, 1);
- curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
- curl_easy_setopt(curl, CURLOPT_COOKIEFILE, "/Users/zhu/CProjects/curlposttest.cookie");
- res = curl_easy_perform(curl);
- curl_easy_cleanup(curl);
- }
- size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp) {
- FILE *fptr = (FILE*)userp;
- fwrite(buffer, size, nmemb, fptr);
- }
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <curl/curl.h>
- #define POSTURL "http://www.xiami.com/member/login"
- #define POSTFIELDS "email=myemail@163.com&password=mypassword&autologin=1&submit=登 录&type="
- #define FILENAME "curlposttest.log"
- size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp);
- int main(int argc, char *argv[]) {
- CURL *curl;
- CURLcode res;
- FILE *fptr;
- struct curl_slist *http_header = NULL;
- if ((fptr = fopen(FILENAME, "w")) == NULL) {
- fprintf(stderr, "fopen file error: %s\n", FILENAME);
- exit(1);
- }
- curl = curl_easy_init();
- curl_easy_setopt(curl, CURLOPT_URL, POSTURL);
- curl_easy_setopt(curl, CURLOPT_POSTFIELDS, POSTFIELDS);
- curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
- curl_easy_setopt(curl, CURLOPT_WRITEDATA, fptr);
- curl_easy_setopt(curl, CURLOPT_POST, 1);
- curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
- curl_easy_setopt(curl, CURLOPT_HEADER, 1);
- curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
- curl_easy_setopt(curl, CURLOPT_COOKIEFILE, "/Users/zhu/CProjects/curlposttest.cookie");
- res = curl_easy_perform(curl);
- curl_easy_cleanup(curl);
- }
- size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp) {
- FILE *fptr = (FILE*)userp;
- fwrite(buffer, size, nmemb, fptr);
- }
2.3 说下这当中的一些操作吧
CURLOPT_URL: URL地址
CURLOPT_POSTFIELDS: POST参数
CURLOPT_WRITEFUNCTION: 对返回的数据进行操作的函数地址
CURLOPT_WRITEDATA: 设置WRITEFUNCTION的第四个参数值
CURLOPT_POST: 设置为非0表示本次操作为POST
CURLOPT_VERBOSE: 设置为非0在执行时打印请求信息
CURLOPT_HEADER: 设置为非0将响应头信息同响应体一起传给WRITEFUNCTION
CURLOPT_FOLLOWLOCATION: 设置为非0，响应头信息Location
CURLOPT_COOKIEFILE: 哈哈，这个实在是太重要了，我之前尝试了好多次没法验证该次POST是否成功的原因就是没有设置这个罗。设置对应的COOKIEFILE路径，该路径文件并不一定需要在物理磁盘上实际存在
2.4 接下来是成功返回的结果哦，呵呵，下面截图当中的zhuzhu可以为证，不好意思，xiami上取了个比较CUO的名字~