當使用C++做HTTP客戶端時，目前通用的做法就是使用libcurl。其官方網站的地址是http://curl.haxx.se/，該網站主要提供了Curl和libcurl。Curl是命令行工具，用於完成FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE 以及 LDAP的命令的請求及接收回饋。libcurl提供給開發者，用於使用C++跨平臺的開發各種網絡協議的請求及響應。裏面的文檔非常齊全，不過都是英文的。

本文提供最簡單的demo使用libcurl開發HttpClient。主要包括同步的HTTP GET、HTTP POST、HTTPS GET、HTTPS POST。

下載libcurl包，如果使用Linux平臺，建議下載源文件編譯；如果使用Windows平臺，建議下載Win32 - MSVC，下載地址是：http://curl.haxx.se/download.html

1. #ifndef __HTTP_CURL_H__
2. #define __HTTP_CURL_H__
4. #include <string>
6. class CHttpClient
7. {
8. public:
9. CHttpClient(void);
10. ~CHttpClient(void);
12. public:
13. /**
14. * @brief HTTP POST請求
15. * @param strUrl 輸入參數,請求的Url地址,如:http://www.baidu.com
16. * @param strPost 輸入參數,使用如下格式para1=val1¶2=val2&…
17. * @param strResponse 輸出參數,返回的內容
18. * @return 返回是否Post成功
19. */
20. int Post(const std::string & strUrl, const std::string & strPost, std::string & strResponse);
22. /**
23. * @brief HTTP GET請求
24. * @param strUrl 輸入參數,請求的Url地址,如:http://www.baidu.com
25. * @param strResponse 輸出參數,返回的內容
26. * @return 返回是否Post成功
27. */
28. int Get(const std::string & strUrl, std::string & strResponse);
30. /**
31. * @brief HTTPS POST請求,無證書版本
32. * @param strUrl 輸入參數,請求的Url地址,如:https://www.alipay.com
33. * @param strPost 輸入參數,使用如下格式para1=val1¶2=val2&…
34. * @param strResponse 輸出參數,返回的內容
35. * @param pCaPath 輸入參數,為CA證書的路徑.如果輸入為NULL,則不驗證服務器端證書的有效性.
36. * @return 返回是否Post成功
37. */
38. int Posts(const std::string & strUrl, const std::string & strPost, std::string & strResponse, const char * pCaPath = NULL);
40. /**
41. * @brief HTTPS GET請求,無證書版本
42. * @param strUrl 輸入參數,請求的Url地址,如:https://www.alipay.com
43. * @param strResponse 輸出參數,返回的內容
44. * @param pCaPath 輸入參數,為CA證書的路徑.如果輸入為NULL,則不驗證服務器端證書的有效性.
45. * @return 返回是否Post成功
46. */
47. int Gets(const std::string & strUrl, std::string & strResponse, const char * pCaPath = NULL);
49. public:
50. void SetDebug(bool bDebug);
52. private:
53. bool m_bDebug;
54. };
56. #endif

1. #include "httpclient.h"
2. #include "curl/curl.h"
3. #include <string>
5. CHttpClient::CHttpClient(void) :
6. m_bDebug(false)
7. {
9. }
11. CHttpClient::~CHttpClient(void)
12. {
14. }
16. static int OnDebug(CURL *, curl_infotype itype, char * pData, size_t size, void *)
17. {
18. if(itype == CURLINFO_TEXT)
19. {
20. //printf("[TEXT]%s\n", pData);
21. }
22. else if(itype == CURLINFO_HEADER_IN)
23. {
24. printf("[HEADER_IN]%s\n", pData);
25. }
26. else if(itype == CURLINFO_HEADER_OUT)
27. {
28. printf("[HEADER_OUT]%s\n", pData);
29. }
30. else if(itype == CURLINFO_DATA_IN)
31. {
32. printf("[DATA_IN]%s\n", pData);
33. }
34. else if(itype == CURLINFO_DATA_OUT)
35. {
36. printf("[DATA_OUT]%s\n", pData);
37. }
38. return 0;
39. }
41. static size_t OnWriteData(void* buffer, size_t size, size_t nmemb, void* lpVoid)
42. {
43. std::string* str = dynamic_cast<std::string*>((std::string *)lpVoid);
44. if( NULL == str || NULL == buffer )
45. {
46. return -1;
47. }
49. char* pData = (char*)buffer;
50. str->append(pData, size * nmemb);
51. return nmemb;
52. }
54. int CHttpClient::Post(const std::string & strUrl, const std::string & strPost, std::string & strResponse)
55. {
56. CURLcode res;
57. CURL* curl = curl_easy_init();
58. if(NULL == curl)
59. {
60. return CURLE_FAILED_INIT;
61. }
62. if(m_bDebug)
63. {
64. curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
65. curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);
66. }
67. curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());
68. curl_easy_setopt(curl, CURLOPT_POST, 1);
69. curl_easy_setopt(curl, CURLOPT_POSTFIELDS, strPost.c_str());
70. curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
71. curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);
72. curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);
73. curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
74. curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);
75. curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
76. res = curl_easy_perform(curl);
77. curl_easy_cleanup(curl);
78. return res;
79. }
81. int CHttpClient::Get(const std::string & strUrl, std::string & strResponse)
82. {
83. CURLcode res;
84. CURL* curl = curl_easy_init();
85. if(NULL == curl)
86. {
87. return CURLE_FAILED_INIT;
88. }
89. if(m_bDebug)
90. {
91. curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
92. curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);
93. }
94. <pre name="code" class="cpp"> curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());
95. curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
96. curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);
97. curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);
98. /**
99. * 當多個線程都使用超時處理的時候，同時主線程中有sleep或是wait等操作。
100. * 如果不設置這個選項，libcurl將會發信號打斷這個wait從而導致程序退出。
101. */
102. curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
103. curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);
104. curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
105. res = curl_easy_perform(curl);
106. curl_easy_cleanup(curl);
107. return res;
108. }
110. int CHttpClient::Posts(const std::string & strUrl, const std::string & strPost, std::string & strResponse, const char * pCaPath)
111. {
112. CURLcode res;
113. CURL* curl = curl_easy_init();
114. if(NULL == curl)
115. {
116. return CURLE_FAILED_INIT;
117. }
118. if(m_bDebug)
119. {
120. curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
121. curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);
122. }
123. curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());
124. curl_easy_setopt(curl, CURLOPT_POST, 1);
125. curl_easy_setopt(curl, CURLOPT_POSTFIELDS, strPost.c_str());
126. curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
127. curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);
128. curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);
129. curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
130. if(NULL == pCaPath)
131. {
132. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
133. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);
134. }
135. else
136. {
137. //缺省情況就是PEM，所以無需設置，另外支持DER
138. //curl_easy_setopt(curl,CURLOPT_SSLCERTTYPE,"PEM");
139. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, true);
140. curl_easy_setopt(curl, CURLOPT_CAINFO, pCaPath);
141. }
142. curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);
143. curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
144. res = curl_easy_perform(curl);
145. curl_easy_cleanup(curl);
146. return res;
147. }
149. int CHttpClient::Gets(const std::string & strUrl, std::string & strResponse, const char * pCaPath)
150. {
151. CURLcode res;
152. CURL* curl = curl_easy_init();
153. if(NULL == curl)
154. {
155. return CURLE_FAILED_INIT;
156. }
157. if(m_bDebug)
158. {
159. curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
160. curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, OnDebug);
161. }
162. curl_easy_setopt(curl, CURLOPT_URL, strUrl.c_str());
163. curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL);
164. curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, OnWriteData);
165. curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&strResponse);
166. curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
167. if(NULL == pCaPath)
168. {
169. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
170. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);
171. }
172. else
173. {
174. curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, true);
175. curl_easy_setopt(curl, CURLOPT_CAINFO, pCaPath);
176. }
177. curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 3);
178. curl_easy_setopt(curl, CURLOPT_TIMEOUT, 3);
179. res = curl_easy_perform(curl);
180. curl_easy_cleanup(curl);
181. return res;
182. }
184. ///////////////////////////////////////////////////////////////////////////////////////////////
186. void CHttpClient::SetDebug(bool bDebug)
187. {
188. m_bDebug = bDebug;
189. }

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1. <br>/wEPDwUJNTc4MTM4MzMzZGQF FxsPex77Sht1ZxPy5wLSXk1lpdzRqG9qS69Ybnkmg==<br>

Re: xiejienet 2013-12-23 01:03發表 [回復]

回復xingtianduiyue：post和get的數據,最好url編碼

C++使用libcurl做HttpClient（業務觀摩，用C++封裝過程式代碼，post和get的數據,最好url編碼，否則+會變成空格）good