Delphi IDHTTP用法详解

一、IDHTTP的基本用法 

2. IDHttp和WebBrowser一样，都可以实现抓取远端网页的功能，但是http方式更快、更节约资源，缺点是需要手动维护cook，连接等 
4. IDHttp的创建，需要引入IDHttp 
6. procedure InitHttp(); 
7. begin
8.     http := TIdHTTP.Create(nil); 
9.     http.ReadTimeout := 30000; 
10.     http.OnRedirect := OnRedirect; 
11.     http.Request.Accept := 'image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*'; 
12.     http.Request.AcceptLanguage := 'zh-cn'; 
13.     http.Request.ContentType := 'application/x-www-form-urlencoded'; 
14.     http.Request.UserAgent := 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 1.1.4322)'; 
16.     http.ProxyParams.ProxyServer := '代理服务器地址'; 
17.     http.ProxyParams.ProxyPort := '代理服务器端口'; 
18. end; 
21. 二、如何取得服务端返回的cookie信息，并添加到http的request对象中 
24. procedure Setcookie; 
25. var
26.    i: Integer; 
27.    tmp, cookie: String; 
28. begin
29.    cookie := ''; 
30. for i := 0 to http.Response.RawHeaders.Count - 1 do
31. begin
32.        tmp := http.Response.RawHeaders[i]; 
33. if pos('set-cookie: ', LowerCase(tmp)) = 0 then Continue; 
34.     tmp := Trim(Copy(tmp, Pos('Set-cookie: ', tmp) + Length('Set-cookie: '), Length(tmp))); 
35.     tmp := Trim(Copy(tmp, 0, Pos(';', tmp) - 1)); 
36. if cookie = '' then cookie := tmp else cookie := cookie + '; ' + tmp; 
37. end; 
38. if cookie <> '' then
39. begin
40. for i := 0 to http.Request.RawHeaders.Count - 1 do
41. begin
42.       tmp := http.Request.RawHeaders[i]; 
43. if Pos('cookie', LowerCase(tmp)) = 0 then Continue; 
44.       http.Request.RawHeaders.Delete(i); 
45.       Break; 
46. end; 
47.     http.Request.RawHeaders.Add('cookie: ' + cookie); 
48. end; 
49. end; 
52. 三、如何取得网页中的所有连接，对代码做修改你也可以实现查找所有图片等等 
55. function GetURLList(Data: String): TStringList; 
56. var
57. i: Integer; 
58. List: TStringList; 
59. tmp: String; 
62. function Split(Data, Node: String): TStringList; 
63. var
64.     Count, i, j: Integer; 
67. function GetFieldCount(Data, Node: String): Integer; 
68. var
69.          i: Integer; 
70. begin
71.           Result := -1; 
72.           i := Pos(Node, Data); 
73. if i = 0 then Exit; 
74.              Result := 0; 
75. while i <> 0 do
76. begin
77.             Inc(Result); 
78.              Delete(Data, 1, i + Length(Node) - 1); 
79.             i := Pos(Node, Data); 
80. end; 
81. end; 
82. begin
83.       Result := TStringList.Create; 
84. Count := GetFieldCount(Data, Node); 
85. for i := 0 to Count - 1 do
86. begin
87.      j := Pos(Node, Data); 
88.      Result.Add(Copy(Data, 1, j - 1)); 
89.      Delete(Data, 1, j + Length(Node) - 1); 
90. end; 
91. Result.Add(Data); 
92. end; 
93. begin
94. Result := TStringList.Create; 
95. try
96.     List := split(Data, 'href='); 
97. for i := 1 to List.Count - 1 do
98. begin
99.       tmp := List[i]; 
100.        tmp := Copy(tmp, 0, Pos('</a>', tmp) - 1); 
101.        tmp := Copy(tmp, 0, Pos('>', tmp) - 1); 
102. if Pos(' ', tmp) <> 0 then
104.           tmp := Copy(tmp, 0, Pos(' ', tmp) - 1); 
105.        tmp := Q_ReplaceStr(tmp, Char(34), ''); 
106.      tmp := Q_ReplaceStr(tmp, Char(39), ''); 
107. if not Compare(CI.Key, tmp) then Continue; 
108. if Copy(tmp, 1, 7) <> 'http://' then
109. begin
110. if Copy(tmp, 1, 1) = '.' then tmp := StringReplace(tmp, '.', '', []); 
111. if Copy(tmp, 1, 1) = '.' then tmp := StringReplace(tmp, '.', '', []); 
112. try
113.          tmp := 'http://' + http.URL.Host + ':' + http.URL.Port + http.URL.Path + tmp; 
114. except
115. end; 
116. end; 
117. if Result.IndexOf(tmp) <> -1 then Continue; 
118.           Result.Add(tmp); 
119. end; 
120.    FreeAndNil(List); 
121. except
123. end; 
124. end; 
127. 四、如何模拟http的get方法打开一个网页 
130. function GetMethod(http: TIDhttp; URL: String; Max: Integer): String; 
131. var
132. RespData: TStringStream; 
133. begin
134. RespData := TStringStream.Create(''); 
135. try
136. try
137.       Http.Get(URL, RespData); 
138.       Http.Request.Referer := URL; 
139.       Result := RespData.DataString; 
140. except
141.       Dec(Max); 
142. if Max = 0 then
143. begin
144.         Result := ''; 
145.         Exit; 
146. end; 
147.       Result := GetMethod(http, URL, Max); 
148. end; 
149. finally
150.     FreeAndNil(RespData); 
151. end; 
152. end; 
155. 五、如何模拟http的post方法提交一个网页 
158. function PostMethod(URL, Data: String; max: Integer): String; 
159. var
160. PostData, RespData: TStringStream; 
161. begin
162. RespData := TStringStream.Create(''); 
163. PostData := TStringStream.Create(Data); 
164. try
165. try
166. if http = nil then Exit; 
167.       Http.Post(URL, PostData, RespData); 
168.       Result := RespData.DataString; 
169.       http.Request.Referer := URL; 
170. except
171.       Dec(Max); 
172. if Max = 0 then
173. begin
174.         Result := ''; 
175.         Exit; 
176. end; 
177.       Result := PostMethod(URL, Data, Max); 
178. end; 
179. finally
180.     http.Disconnect; 
181.     FreeAndNil(RespData); 
182.     FreeAndNil(PostData); 
183. end; 
184. end; 
187. 六、伪造session 
189. var
190. My_Cookie,tmpcookie:string; 
192. begin
193. aIdHttp.Get('http://www.huochepiao.net/'); 
194. tmpcookie:=aIdHttp.Request.CustomHeaders.Values['Set-Cookie']; 
195. if Pos(';',tmpcookie)>0 then
196.      My_Cookie:=LeftBStr(tmpcookie,Pos(';',tmpcookie)-1) 
197. else
198.      My_Cookie:= tmpcookie; 
199. //
200. aIdHTTP.Request.CustomHeaders.Clear; 
201. aIdHTTP.Request.CustomHeaders.Add('Cookie:'+My_COOKIE); 
203. end;