libcurl上傳文件實例

libcurl上傳文件實例

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Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with CURLOPT_HTTPHEADER as usual.

When setting CURLOPT_HTTPPOST, it will automatically set CURLOPT_NOBODY to 0 (since 7.14.1).

 

CURLOPT_POST   --application/x-www-form-urlencoded形式

A non-zero parameter tells the library to do a regular HTTP post. This will also make the library use the a "Content-Type: application/x-www-form-urlencoded" header. (This is by far the most commonly used POST method).

Use one of CURLOPT_POSTFIELDS or CURLOPT_COPYPOSTFIELDS options to specify what data to post and CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE to set the data size.

Optionally, you can provide data to POST using the CURLOPT_READFUNCTION and CURLOPT_READDATA options but then you must make sure to not set CURLOPT_POSTFIELDS to anything but NULL. When providing data with a callback, you must transmit it using chunked transfer-encoding or you must set the size of the data with the CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE option. To enable chunked encoding, you simply pass in the appropriate Transfer-Encoding header, see the post-callback.c example.

You can override the default POST Content-Type: header by setting your own with CURLOPT_HTTPHEADER.

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with CURLOPT_HTTPHEADER as usual.

If you use POST to a HTTP 1.1 server, you can send data without knowing the size before starting the POST if you use chunked encoding. You enable this by adding a header like "Transfer-Encoding: chunked" with CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must specify the size in the request.

When setting CURLOPT_POST to a non-zero value, it will automatically set CURLOPT_NOBODY to 0 (since 7.14.1).

If you issue a POST request and then want to make a HEAD or GET using the same re-used handle, you must explicitly set the new request type using CURLOPT_NOBODY or CURLOPT_HTTPGET or similar.

以上是兩種POST方式，具體代碼以下:

    ALLUPLOADFILES::iterator iter = allFiles.begin();
    //若是含有文件 //name="files"; filename="file1.txt"    
    if( bFileFlag ) //以form-dataf方式post
    {
        for (;iter != allFiles.end();iter++)
        {
            if ( iter->isFile )
            {
                my_bytestr_url_encode(iter->fileName);
                curl_formadd(&post, &last, CURLFORM_COPYNAME , iter->contrlID.c_str(),
                    CURLFORM_BUFFER, iter->fileName.c_str(),
                    CURLFORM_BUFFERPTR,iter->data.c_str(),
                    CURLFORM_END);    
            }
            else
            {
                curl_formadd(&post, &last, CURLFORM_COPYNAME , iter->contrlID.c_str(),
                    CURLFORM_COPYCONTENTS,iter->data.c_str(),
                    CURLFORM_END);    
            }
        }
    }
    else //以application/x-www-form-urlencoded方式post
    {
        for (;iter != allFiles.end();iter++)
        {
            my_bytestr_url_encode(iter->contrlID);
            my_bytestr_url_encode(iter->data);
            postbuffer += iter->contrlID;
            postbuffer += "=";
            postbuffer += iter->data;
            postbuffer += "&";
        }
    }


    if (bFileFlag) 
        curl_easy_setopt(curl, CURLOPT_HTTPPOST,post);
    else 
    {
        curl_easy_setopt(curl, CURLOPT_POST,1);
        curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS  , postbuffer.c_str());
    }

    code = curl_easy_perform(curl);

對於返回頁面，咱們能夠和上一篇文章所說那樣，設置write的回調函數，寫入文件便可：

    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer);

long writer(void *data, int size, int nmemb, string &content)
{
    long sizes = size * nmemb;
    string temp(data,sizes);
    printf("receive data(%d bytes):\r\n%s",  sizes, (char*)data );
    content += temp; 
    return sizes;
}

測試：
咱們能夠用tomcat寫一個jsp上傳代碼測試一下，其中使用到了smartUpload組件，代碼以下：upload.html

<form action="upload.jsp" method="post" ENCTYPE="multipart/form-data">

輸入名稱:<input type="type" name="name"><br>

選擇要上傳的圖片:

<input type="file" name="pic">

<input type="submit" value="上傳">

</form>

upload.jsp以下:

<jsp:useBean id="smart" scope="page" class="org.lxh.smart.SmartUpload"/>

<%
       //上傳初始化
       smart.initialize(pageContext);
       //準備上傳
       smart.upload();     
       //保存上傳的文件
       //smart.save("/upload");
       //取得文件的擴展名稱
       String ext = smart.getFiles().getFile(0).getFileExt();
%>
<%
       //String name=request.getParameter("name"); 表單被封裝了,不能用這種方法取值.
       String name=smart.getRequest().getParameter("name");
%> 

       //<%=name+"."+ext%>
<%       //保存文件,包括更名.
       smart.getFiles().getFile(0).saveAs("/upload/"+name+"."+ext);
%>