如何使用 libcurl 登录本网站?(C++）

How do I use libcurl to log into this website? (C++)

本文关键字：C++ 网站 何使用 libcurl 登录      更新时间：2023-10-16

我想制作一个C++程序来填写带有登录凭据的HTML网络表单(我目前将其硬编码到用户名和密码字段中)，然后提交网络表单并进入下一个HTML页面。

使用下面的代码，它一直卡在登录页面上并且无法继续前进。在控制台中，我不断获取登录页面的 HTML 源代码，而不是登录后出现的页面。

有人可以一步一步地指导我吗？

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
int main()
{
curl_global_init( CURL_GLOBAL_ALL );
CURL * myHandle = curl_easy_init ( );
// Set up a couple initial paramaters that we will not need to mofiy later.
curl_easy_setopt(myHandle, CURLOPT_USERAGENT, "Mozilla/5.0");
curl_easy_setopt(myHandle, CURLOPT_AUTOREFERER, 1 );
curl_easy_setopt(myHandle, CURLOPT_FOLLOWLOCATION, 1 );
curl_easy_setopt(myHandle, CURLOPT_COOKIEFILE, "");
// Visit the login page once to obtain a PHPSESSID cookie
curl_easy_setopt(myHandle, CURLOPT_URL, "website login page URL here");
curl_easy_perform( myHandle );
// Now, can actually login. First we forge the HTTP referer field, or HTS will deny the login
curl_easy_setopt(myHandle, CURLOPT_REFERER, "website login page URL here");
// Next we tell LibCurl what HTTP POST data to submit
char *data="ctl00$LoginTextBox=USERNAME&ctl00$PasswordTextbox=PASSWORD&ctl00$LogInButton=Sign in&ctl00$HiddenValue=Initial Value";
curl_easy_setopt(myHandle, CURLOPT_POSTFIELDS, data);
curl_easy_perform( myHandle );
curl_easy_cleanup( myHandle );
return 0;
}

这是我正在处理的 HTML 网络表单：

<div id="loginForm">
<div id="loginInput">
<label for="ctl00_LoginTextBox" id="ctl00_LoginLabel">Name/Badge</label>
<input name="ctl00$LoginTextBox" type="text" id="ctl00_LoginTextBox" class="PopupInput" />
</div>
<div id="passwordInput">
<label for="ctl00_PasswordTextbox" id="ctl00_PasswordLabel">Password</label>
<input name="ctl00$PasswordTextbox" type="password" id="ctl00_PasswordTextbox" class="PopupInput" />        
</div>
<div id="equipmentbox">
</div>
</div>
<div id="ctl00_LoginButtons">
<input type="submit" name="ctl00$LogInButton" value="Sign in" id="ctl00_LogInButton" class="btn" />
<input type="submit" name="ctl00$SwitchLoginScreenModeBT" value="Change Password" id="ctl00_SwitchLoginScreenModeBT" class="btn" /> 
</div>
<input name="ctl00$HiddenValue" type="hidden" id="ctl00_HiddenValue" value="Initial Value" />
<input name="ctl00$HiddenValue2" type="hidden" id="ctl00_HiddenValue2" value="Initial Value" />

你的代码有两个问题：

  • 您的data未完全正确进行网址编码。 您可以(并且应该)使用curl_easy_escape()正确编码您发布的每个name和valuename=value对的每个组件CURLOPT_POSTFIELDS.

  • 您使用CURLOPT_POSTFIELDS发布data，它以application/x-www-form-urlencoded格式发布(这是许多在线网络表单的默认设置)，但有问题的特定网络表单实际上希望data以multipart/form-data格式发布(由于网络表单的enctype="multipart/form-data"属性)，因此您需要改用CURLOPT_HTTPPOST(已弃用)或CURLOPT_MIMEPOST。

尝试更多类似的东西：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
int main()
{
curl_global_init(CURL_GLOBAL_ALL);
CURL *myHandle = curl_easy_init();
// Set up a couple initial paramaters that we will not need to mofiy later.
curl_easy_setopt(myHandle, CURLOPT_USERAGENT, "Mozilla/5.0");
curl_easy_setopt(myHandle, CURLOPT_AUTOREFERER, 1);
curl_easy_setopt(myHandle, CURLOPT_FOLLOWLOCATION, 1);
curl_easy_setopt(myHandle, CURLOPT_COOKIEFILE, "");
// Visit the login page once to obtain a PHPSESSID cookie
curl_easy_setopt(myHandle, CURLOPT_URL, "website login page URL here");
curl_easy_perform(myHandle);
// Now, can actually login. First we forge the HTTP referer field, or HTS will deny the login
curl_easy_setopt(myHandle, CURLOPT_REFERER, "website login page URL here");
// Next we tell LibCurl what HTTP POST data to submit
struct curl_httppost *data = NULL;
struct curl_httppost *last = NULL;
curl_formadd(&data, &last, CURLFORM_PTRNAME, "ctl00$LoginTextBox", CURLFORM_PTRCONTENTS, "USERNAME", CURLFORM_END);
curl_formadd(&data, &last, CURLFORM_PTRNAME, "ctl00$PasswordTextbox", CURLFORM_PTRCONTENTS, "PASSWORD", CURLFORM_END);
curl_formadd(&data, &last, CURLFORM_PTRNAME, "ctl00$LogInButton", CURLFORM_PTRCONTENTS, "Sign in", CURLFORM_END);
curl_formadd(&data, &last, CURLFORM_PTRNAME, "ctl00$HiddenValue", CURLFORM_PTRCONTENTS, "Initial Value", CURLFORM_END);
curl_easy_setopt(myHandle, CURLOPT_HTTPPOST, data);
curl_easy_perform(myHandle);
curl_formfree(data);
curl_easy_cleanup(myHandle);
return 0;
}

或者这个：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
int main()
{
curl_global_init(CURL_GLOBAL_ALL);
CURL *myHandle = curl_easy_init();
// Set up a couple initial paramaters that we will not need to mofiy later.
curl_easy_setopt(myHandle, CURLOPT_USERAGENT, "Mozilla/5.0");
curl_easy_setopt(myHandle, CURLOPT_AUTOREFERER, 1);
curl_easy_setopt(myHandle, CURLOPT_FOLLOWLOCATION, 1);
curl_easy_setopt(myHandle, CURLOPT_COOKIEFILE, "");
// Visit the login page once to obtain a PHPSESSID cookie
curl_easy_setopt(myHandle, CURLOPT_URL, "website login page URL here");
curl_easy_perform(myHandle);
// Now, can actually login. First we forge the HTTP referer field, or HTS will deny the login
curl_easy_setopt(myHandle, CURLOPT_REFERER, "website login page URL here");
// Next we tell LibCurl what HTTP POST data to submit
curl_mime *mime = curl_mime_init(myHandle);
curl_mimepart *part = curl_mime_addpart(mime);
curl_mime_name(part, "ctl00$LoginTextBox");
curl_mime_data(part, "USERNAME", CURL_ZERO_TERMINATED);
part = curl_mime_addpart(mime);
curl_mime_name(part, "ctl00$PasswordTextbox");
curl_mime_data(part, "PASSWORD", CURL_ZERO_TERMINATED);
part = curl_mime_addpart(mime);
curl_mime_name(part, "ctl00$LogInButton");
curl_mime_data(part, "Sign in", CURL_ZERO_TERMINATED);
part = curl_mime_addpart(mime);
curl_mime_name(part, "ctl00$HiddenValue");
curl_mime_data(part, "Initial Value", CURL_ZERO_TERMINATED);
curl_easy_setopt(myHandle, CURLOPT_MIMEPOST, data);
curl_easy_perform(myHandle);
curl_mime_free(mime);
curl_easy_cleanup(myHandle);
return 0;
}
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