Delphi IDHTTP用法详解

一、IDHTTP的基本用法 

1. 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 
2. IDHttp的创建，需要引入IDHttp 
3. procedure InitHttp(); 
4. begin
5.     http := TIdHTTP.Create(nil); 
6.     http.ReadTimeout := 30000; 
7.     http.OnRedirect := OnRedirect; 
8.     http.Request.Accept := 'image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*'; 
9.     http.Request.AcceptLanguage := 'zh-cn'; 
10.     http.Request.ContentType := 'application/x-www-form-urlencoded'; 
11.     http.Request.UserAgent := 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 1.1.4322)'; 
12.     http.ProxyParams.ProxyServer := '代理服务器地址'; 
13.     http.ProxyParams.ProxyPort := '代理服务器端口'; 
14. end; 
15. 二、如何取得服务端返回的cookie信息，并添加到http的request对象中 
16. procedure Setcookie; 
17. var
18.    i: Integer; 
19.    tmp, cookie: String; 
20. begin
21.    cookie := ''; 
22. for i := 0 to http.Response.RawHeaders.Count - 1 do
23. begin
24.        tmp := http.Response.RawHeaders[i]; 
25. if pos('set-cookie: ', LowerCase(tmp)) = 0 then Continue; 
26.     tmp := Trim(Copy(tmp, Pos('Set-cookie: ', tmp) + Length('Set-cookie: '), Length(tmp))); 
27.     tmp := Trim(Copy(tmp, 0, Pos(';', tmp) - 1)); 
28. if cookie = '' then cookie := tmp else cookie := cookie + '; ' + tmp; 
29. end; 
30. if cookie <> '' then
31. begin
32. for i := 0 to http.Request.RawHeaders.Count - 1 do
33. begin
34.       tmp := http.Request.RawHeaders[i]; 
35. if Pos('cookie', LowerCase(tmp)) = 0 then Continue; 
36.       http.Request.RawHeaders.Delete(i); 
37.       Break; 
38. end; 
39.     http.Request.RawHeaders.Add('cookie: ' + cookie); 
40. end; 
41. end; 
42. 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 
43. function GetURLList(Data: String): TStringList; 
44. var
45. i: Integer; 
46. List: TStringList; 
47. tmp: String; 
48. function Split(Data, Node: String): TStringList; 
49. var
50.     Count, i, j: Integer; 
51. function GetFieldCount(Data, Node: String): Integer; 
52. var
53.          i: Integer; 
54. begin
55.           Result := -1; 
56.           i := Pos(Node, Data); 
57. if i = 0 then Exit; 
58.              Result := 0; 
59. while i <> 0 do
60. begin
61.             Inc(Result); 
62.              Delete(Data, 1, i + Length(Node) - 1); 
63.             i := Pos(Node, Data); 
64. end; 
65. end; 
66. begin
67.       Result := TStringList.Create; 
68. Count := GetFieldCount(Data, Node); 
69. for i := 0 to Count - 1 do
70. begin
71.      j := Pos(Node, Data); 
72.      Result.Add(Copy(Data, 1, j - 1)); 
73.      Delete(Data, 1, j + Length(Node) - 1); 
74. end; 
75. Result.Add(Data); 
76. end; 
77. begin
78. Result := TStringList.Create; 
79. try
80.     List := split(Data, 'href='); 
81. for i := 1 to List.Count - 1 do
82. begin
83.       tmp := List[i]; 
84.        tmp := Copy(tmp, 0, Pos('</a>', tmp) - 1); 
85.        tmp := Copy(tmp, 0, Pos('>', tmp) - 1); 
86. if Pos(' ', tmp) <> 0 then
87.           tmp := Copy(tmp, 0, Pos(' ', tmp) - 1); 
88.        tmp := Q_ReplaceStr(tmp, Char(34), ''); 
89.      tmp := Q_ReplaceStr(tmp, Char(39), ''); 
90. if not Compare(CI.Key, tmp) then Continue; 
91. if Copy(tmp, 1, 7) <> 'http://' then
92. begin
93. if Copy(tmp, 1, 1) = '.' then tmp := StringReplace(tmp, '.', '', []); 
94. if Copy(tmp, 1, 1) = '.' then tmp := StringReplace(tmp, '.', '', []); 
95. try
96.          tmp := 'http://' + http.URL.Host + ':' + http.URL.Port + http.URL.Path + tmp; 
97. except
98. end; 
99. end; 
100. if Result.IndexOf(tmp) <> -1 then Continue; 
101.           Result.Add(tmp); 
102. end; 
103.    FreeAndNil(List); 
104. except
105. end; 
106. end; 
107. 四、如何模拟http的get方法打开一个网页 
108. function GetMethod(http: TIDhttp; URL: String; Max: Integer): String; 
109. var
110. RespData: TStringStream; 
111. begin
112. RespData := TStringStream.Create(''); 
113. try
114. try
115.       Http.Get(URL, RespData); 
116.       Http.Request.Referer := URL; 
117.       Result := RespData.DataString; 
118. except
119.       Dec(Max); 
120. if Max = 0 then
121. begin
122.         Result := ''; 
123.         Exit; 
124. end; 
125.       Result := GetMethod(http, URL, Max); 
126. end; 
127. finally
128.     FreeAndNil(RespData); 
129. end; 
130. end; 
131. 五、如何模拟http的post方法提交一个网页 
132. function PostMethod(URL, Data: String; max: Integer): String; 
133. var
134. PostData, RespData: TStringStream; 
135. begin
136. RespData := TStringStream.Create(''); 
137. PostData := TStringStream.Create(Data); 
138. try
139. try
140. if http = nil then Exit; 
141.       Http.Post(URL, PostData, RespData); 
142.       Result := RespData.DataString; 
143.       http.Request.Referer := URL; 
144. except
145.       Dec(Max); 
146. if Max = 0 then
147. begin
148.         Result := ''; 
149.         Exit; 
150. end; 
151.       Result := PostMethod(URL, Data, Max); 
152. end; 
153. finally
154.     http.Disconnect; 
155.     FreeAndNil(RespData); 
156.     FreeAndNil(PostData); 
157. end; 
158. end; 
159. 六、伪造session 
160. var
161. My_Cookie,tmpcookie:string; 
162. begin
163. aIdHttp.Get('http://www.huochepiao.net/'); 
164. tmpcookie:=aIdHttp.Request.CustomHeaders.Values['Set-Cookie']; 
165. if Pos(';',tmpcookie)>0 then
166.      My_Cookie:=LeftBStr(tmpcookie,Pos(';',tmpcookie)-1) 
167. else
168.      My_Cookie:= tmpcookie; 
169. //
170. aIdHTTP.Request.CustomHeaders.Clear; 
171. aIdHTTP.Request.CustomHeaders.Add('Cookie:'+My_COOKIE); 
172. end;