使用WinINet和WinHTTP实现Http访问
Http访问有两种方式，GET和POST，就编程来说GET方式相对简单点，它不用向服务器提交数据，在这个例程中我使用POST方式，提交数据value1与value2，并从服务器得到他们的和（value1 + value2）。
为实现Http访问，微软提供了二套API：WinINet, WinHTTP。WinHTTP比WinINet更加安全和健壮，可以这么认为WinHTTP是WinINet的升级版本。这两套API包含了很多相似的函数与宏定义，呵呵，详细对比请查阅msdn中的文章“Porting WinINet Applications to WinHTTP”，在线MSDN连接：http://msdn2.microsoft.com/en-us/library/aa384068.aspx。在这个例程中，通过一个宏的设置来决定是使用WinHttp还是WinINet。代码如下:
#define USE_WINHTTP //Comment this line to user wininet.
下面来说说实现Http访问的流程（两套API都一样的流程）：
1， 首先我们打开一个Session获得一个HINTERNET session句柄；
2， 然后我们使用这个session句柄与服务器连接得到一个HINTERNET connect句柄；
3， 然后我们使用这个connect句柄来打开Http 请求得到一个HINTERNET request句柄；
4， 这时我们就可以使用这个request句柄来发送数据与读取从服务器返回的数据；
5， 最后依次关闭request，connect，session句柄。
在这个例程中以上各个流程都进行了简单封装，以便对比两套API函数的些许差异。下面让源代码说话，原工程是一个windows控制台工程，你可以很容易通过拷贝代码重建工程。
另：如果你从服务器得到的返回数据是utf8格式的文本数据，你将需要对返回的数据进行转换才能正确显示中文，日文等。仅供参考，转换为ATL CStringW的函数见下：
CStringW GetStringWFromUtf8(const std::string& str)
{
int len = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), int(str.length()), 0, 0);
CStringW buf;
WCHAR* dd = buf.GetBuffer(len);
len = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), int(str.length()), dd, len);
buf.ReleaseBuffer(len);
return buf;
}
完整代码如下：
1// HttpPost.cpp written by l_zhaohui@163.com
2// 2007/11/30
3 #include "stdafx.h"
4 #include <windows.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7
8 #define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS
9 #include <atlbase.h>
10 #include <atlstr.h>
11
12 #define USE_WINHTTP //Comment this line to user wininet.
13 #ifdef USE_WINHTTP
14 #include <winhttp.h>
15 #pragma comment(lib, "winhttp.lib")
16 #else
17 #include <wininet.h>
18 #pragma comment(lib, "wininet.lib")
19 #endif
20 #define BUF_SIZE (1024)
21
22 // CrackedUrl
23 class CrackedUrl {
24 int m_scheme;
25 CStringW m_host;
26 int m_port;
27 CStringW m_path;
28 public:
29 CrackedUrl(LPCWSTR url)
30 {
31 URL_COMPONENTS uc = { 0};
32 uc.dwStructSize = sizeof(uc);
33
34 const DWORD BUF_LEN = 256;
35
36 WCHAR host[BUF_LEN];
37 uc.lpszHostName = host;
38 uc.dwHostNameLength = BUF_LEN;
39
40 WCHAR path[BUF_LEN];
41 uc.lpszUrlPath = path;
42 uc.dwUrlPathLength = BUF_LEN;
43
44 WCHAR extra[BUF_LEN];
45 uc.lpszExtraInfo = extra;
46 uc.dwExtraInfoLength = BUF_LEN;
47
48 #ifdef USE_WINHTTP
49 if (!WinHttpCrackUrl(url, 0, ICU_ESCAPE, &uc)) {
50 printf("Error:WinHttpCrackUrl failed!
");
51 }
52
53 #else
54 if (!InternetCrackUrl(url, 0, ICU_ESCAPE, &uc)) {
55 printf("Error:InternetCrackUrl failed!
");
56 }
57 #endif
58 m_scheme = uc.nScheme;
59 m_host = host;
60 m_port = uc.nPort;
61 m_path = path;
62 }
63
64 int GetScheme() const
65 {
66 return m_scheme;
67 }
68
69 LPCWSTR GetHostName() const
70 {
71 return m_host;
72 }
73
74 int GetPort() const
75 {
76 return m_port;
77 }
78
79 LPCWSTR GetPath() const
80 {
81 return m_path;
82 }
83
84 static CStringA UrlEncode(const char* p)
85 {
86 if (p == 0) {
87 return CStringA();
88 }
89
90 CStringA buf;
91
92 for (;;) {
93 int ch = (BYTE) (*(p++));
94 if (ch == ' ') {
95 break;
96 }
97
98 if (isalnum(ch) || ch == '_' || ch == '-' || ch == '.') {
99 buf += (char)ch;
100 }
101 else if (ch == ' ') {
102 buf += '+';
103 }
104 else {
105 char c[16];
106 wsprintfA(c, "%%%02X", ch);
107 buf += c;
108 }
109 }
110
111 return buf;
112 }
113 };
114
115 // CrackedUrl
116 HINTERNET OpenSession(LPCWSTR userAgent = 0)
117 {
118 #ifdef USE_WINHTTP
119 return WinHttpOpen(userAgent, NULL, NULL, NULL, NULL);;
120 #else
121 return InternetOpen(userAgent, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
122 #endif
123}
124
125 HINTERNET Connect(HINTERNET hSession, LPCWSTR serverAddr, int portNo)
126 {
127 #ifdef USE_WINHTTP
128 return WinHttpConnect(hSession, serverAddr, (INTERNET_PORT) portNo, 0);
129 #else
130 return InternetConnect(hSession, serverAddr, portNo, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
131 #endif
132 }
133
134 HINTERNET OpenRequest(HINTERNET hConnect, LPCWSTR verb, LPCWSTR objectName, int scheme)
135 {
136 DWORD flags = 0;
137 #ifdef USE_WINHTTP
138 if (scheme == INTERNET_SCHEME_HTTPS) {
139 flags |= WINHTTP_FLAG_SECURE;
140 }
141
142 return WinHttpOpenRequest(hConnect, verb, objectName, NULL, NULL, NULL, flags);
143
144 #else
145 if (scheme == INTERNET_SCHEME_HTTPS) {
146 flags |= INTERNET_FLAG_SECURE;
147 }
148
149 return HttpOpenRequest(hConnect, verb, objectName, NULL, NULL, NULL, flags, 0);
150 #endif
151}
152
153 BOOL AddRequestHeaders(HINTERNET hRequest, LPCWSTR header)
154 {
155 SIZE_T len = lstrlenW(header);
156 #ifdef USE_WINHTTP
157 return WinHttpAddRequestHeaders(hRequest, header, DWORD(len), WINHTTP_ADDREQ_FLAG_ADD);
158 #else
159 return HttpAddRequestHeaders(hRequest, header, DWORD(len), HTTP_ADDREQ_FLAG_ADD);
160 #endif
161 }
162
163 BOOL SendRequest(HINTERNET hRequest, const void* body, DWORD size)
164 {
165 #ifdef USE_WINHTTP
166 return WinHttpSendRequest(hRequest, 0, 0, const_cast<void*>(body), size, size, 0);
167 #else
168 return HttpSendRequest(hRequest, 0, 0, const_cast<void*>(body), size);
169 #endif
170 }
171
172 BOOL EndRequest(HINTERNET hRequest)
173 {
174 #ifdef USE_WINHTTP
175 return WinHttpReceiveResponse(hRequest, 0);
176 #else
177 // if you use HttpSendRequestEx to send request then use HttpEndRequest in here!
178 return TRUE;
179 #endif
180}
181
182 BOOL QueryInfo(HINTERNET hRequest, int queryId, char* szBuf, DWORD* pdwSize)
183 {
184 #ifdef USE_WINHTTP
185 return WinHttpQueryHeaders(hRequest, (DWORD) queryId, 0, szBuf, pdwSize, 0);
186 #else
187 return HttpQueryInfo(hRequest, queryId, szBuf, pdwSize, 0);
188 #endif
189}
190
191 BOOL ReadData(HINTERNET hRequest, void* buffer, DWORD length, DWORD* cbRead)
192 {
193 #ifdef USE_WINHTTP
194 return WinHttpReadData(hRequest, buffer, length, cbRead);
195 #else
196 return InternetReadFile(hRequest, buffer, length, cbRead);
197 #endif
198}
199
200 void CloseInternetHandle(HINTERNET hInternet)
201 {
202 if (hInternet)
203 {
204 #ifdef USE_WINHTTP
205 WinHttpCloseHandle(hInternet);
206 #else
207 InternetCloseHandle(hInternet);
208 #endif
209 }
210}
211
212 int _tmain(int argc, _TCHAR* argv[])
213 {
214 HINTERNET hSession = 0;
215 HINTERNET hConnect = 0;
216 HINTERNET hRequest = 0;
217 CStringW strHeader(L"Content-type: application/x-www-form-urlencoded
");
218
219 // Test data
220 CrackedUrl crackedUrl(L"http://www.easy-creator.net/test2/add.asp");
221 CStringA strPostData("value1=10&value2=14");
222
223 // Open session.
224 hSession = OpenSession(L"HttpPost by l_zhaohui@163.com");
225 if (hSession == NULL) {
226 printf("Error:Open session!
");
227 return -1;
228 }
229
230 // Connect.
231 hConnect = Connect(hSession, crackedUrl.GetHostName(), crackedUrl.GetPort());
232 if (hConnect == NULL) {
233 printf("Error:Connect failed!
");
234 return -1;
235 }
236
237 // Open request.
238 hRequest = OpenRequest(hConnect, L"POST", crackedUrl.GetPath(), crackedUrl.GetScheme());
239 if (hRequest == NULL) {
240 printf("Error:OpenRequest failed!
");
241 return -1;
242 }
243
244 // Add request header.
245 if (!AddRequestHeaders(hRequest, strHeader)) {
246 printf("Error:AddRequestHeaders failed!
");
247 return -1;
248 }
249
250 // Send post data.
251 if (!SendRequest(hRequest, (const char*)strPostData, strPostData.GetLength())) {
252 printf("Error:SendRequest failed!
");
253 return -1;
254 }
255
256 // End request
257 if (!EndRequest(hRequest)) {
258 printf("Error:EndRequest failed!
");
259 return -1;
260 }
261
262 char szBuf[BUF_SIZE];
263 DWORD dwSize = 0;
264 szBuf[0] = 0;
265
266 // Query header info.
267 #ifdef USE_WINHTTP
268 int contextLengthId = WINHTTP_QUERY_CONTENT_LENGTH;
269 int statusCodeId = WINHTTP_QUERY_STATUS_CODE;
270 int statusTextId = WINHTTP_QUERY_STATUS_TEXT;
271 #else
272 int contextLengthId = HTTP_QUERY_CONTENT_LENGTH;
273 int statusCodeId = HTTP_QUERY_STATUS_CODE;
274 int statusTextId = HTTP_QUERY_STATUS_TEXT;
275 #endif
276 dwSize = BUF_SIZE;
277 if (QueryInfo(hRequest, contextLengthId, szBuf, &dwSize)) {
278 szBuf[dwSize] = 0;
279 printf("Content length:[%s]
", szBuf);
280 }
281
282 dwSize = BUF_SIZE;
283 if (QueryInfo(hRequest, statusCodeId, szBuf, &dwSize)) {
284 szBuf[dwSize] = 0;
285 printf("Status code:[%s]
", szBuf);
286 }
287
288 dwSize = BUF_SIZE;
289 if (QueryInfo(hRequest, statusTextId, szBuf, &dwSize)) {
290 szBuf[dwSize] = 0;
291 printf("Status text:[%s]
", szBuf);
292 }
293
294 // read data.
295 for (;;) {
296 dwSize = BUF_SIZE;
297 if (ReadData(hRequest, szBuf, dwSize, &dwSize) == FALSE) {
298 break;
299 }
300
301 if (dwSize <= 0) {
302 break;
303 }
304
305 szBuf[dwSize] = 0;
306 printf("%s
", szBuf); //Output value = value1 + value2
307 }
308
309 CloseInternetHandle(hRequest);
310 CloseInternetHandle(hConnect);
311 CloseInternetHandle(hSession);
312
313 return 0;
314}
315