使用WinINet和WinHTTP實現Http訪問
飄飄白云 l_zhaohui@163.com 2007-11-30
Http訪問有兩種方式，GET和POST，就編程來說GET方式相對簡單點，它不用向服務器提交數據，在這個例程中我使用POST方式，提交數據value1與value2，并從服務器得到他們的和（value1 + value2）。
為實現Http訪問，微軟提供了二套API：WinINet, WinHTTP。WinHTTP比WinINet更加安全和健壯，可以這么認為WinHTTP是WinINet的升級版本。這兩套API包含了很多相似的函數與宏定義，呵呵，詳細對比請查閱msdn中的文章“Porting WinINet Applications to WinHTTP”，在線MSDN連接：http://msdn2.microsoft.com/en-us/library/aa384068.aspx。在這個例程中，通過一個宏的設置來決定是使用WinHttp還是WinINet。代碼如下:
#define USE_WINHTTP //Comment this line to user wininet.
下面來說說實現Http訪問的流程（兩套API都一樣的流程）：
1， 首先我們打開一個Session獲得一個HINTERNET session句柄；
2， 然后我們使用這個session句柄與服務器連接得到一個HINTERNET connect句柄；
3， 然后我們使用這個connect句柄來打開Http 請求得到一個HINTERNET request句柄；
4， 這時我們就可以使用這個request句柄來發送數據與讀取從服務器返回的數據；
5， 最后依次關閉request，connect，session句柄。
在這個例程中以上各個流程都進行了簡單封裝，以便對比兩套API函數的些許差異。下面讓源代碼說話，原工程是一個windows控制臺工程，你可以很容易通過拷貝代碼重建工程。
另：如果你從服務器得到的返回數據是utf8格式的文本數據，你將需要對返回的數據進行轉換才能正確顯示中文，日文等。僅供參考，轉換為ATL CStringW的函數見下：
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;
}完整代碼如下：
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
23class CrackedUrl {
24 int m_scheme;
25 CStringW m_host;
26 int m_port;
27 CStringW m_path;
28public:
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!\n");
51
}
52
53#else
54 if (!InternetCrackUrl(url, 0, ICU_ESCAPE, &uc)) {
55 printf("Error:InternetCrackUrl failed!\n");
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 == '\0') {
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
116HINTERNET 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
125HINTERNET 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
134HINTERNET 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
153BOOL 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
163BOOL 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
172BOOL 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
182BOOL 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
191BOOL 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
200void 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
212int _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\r\n");
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!\n");
227 return -1;
228 }
229
230 // Connect.
231 hConnect = Connect(hSession, crackedUrl.GetHostName(), crackedUrl.GetPort());
232 if (hConnect == NULL) {
233 printf("Error:Connect failed!\n");
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!\n");
241 return -1;
242 }
243
244 // Add request header.
245 if (!AddRequestHeaders(hRequest, strHeader)) {
246 printf("Error:AddRequestHeaders failed!\n");
247 return -1;
248 }
249
250 // Send post data.
251 if (!SendRequest(hRequest, (const char*)strPostData, strPostData.GetLength())) {
252 printf("Error:SendRequest failed!\n");
253 return -1;
254 }
255
256 // End request
257 if (!EndRequest(hRequest)) {
258 printf("Error:EndRequest failed!\n");
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]\n", szBuf);
280 }
281
282 dwSize = BUF_SIZE;
283 if (QueryInfo(hRequest, statusCodeId, szBuf, &dwSize)) {
284 szBuf[dwSize] = 0;
285 printf("Status code:[%s]\n", szBuf);
286 }
287
288 dwSize = BUF_SIZE;
289 if (QueryInfo(hRequest, statusTextId, szBuf, &dwSize)) {
290 szBuf[dwSize] = 0;
291 printf("Status text:[%s]\n", 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\n", szBuf); //Output value = value1 + value2
307 }
308
309 CloseInternetHandle(hRequest);
310 CloseInternetHandle(hConnect);
311 CloseInternetHandle(hSession);
312
313 return 0;
314}
315