从网上获取文件：在GTK中使用C [英] Fetch a file from web: in GTK using C

问题描述

如果我的文件来自：

$ b $使用gtk库可以从网络获取文件的功能b

gchar * path =http：//xxx.yyyServer/sharing/temp.txt

我应该怎么下载它？

对于本地文件，我只是简单地使用C库，如fopen和fread。

我应该如何进行上述操作？

>

很遗憾，教程中没有文件处理的例子。我只能从文件对话框中看到一个文件选择器。

请帮助这个noob。
$ b

谢谢

p>

使用注释工作代码进行更新：
以下代码适用于大小未知的二进制文件。

  char * name = http://127.0.0.1:8000/mybinfile 
 
 $ b $ int getFile（char * name）
 {
 
 GFile * f = g_file_new_for_uri（name）; 
 GFileInputStream * fis = NULL; 
 GDataInputStream * dis = NULL; 
 GError * err = NULL; 
 // char buffer [2048]; 
 char * buffer; 
 size_t length; 
 int ret = -1; 
 
 GFileInfo * info; 
 
 int total_size = -1; 
 
 / *获得输入流* / 
 fis = g_file_read（f，NULL，& err）; 
 $ b $ if（err！= NULL）{
 fprintf（stderr，ERROR：opening％s\\\
，name）; 
 g_object_unref（f）; 
返回-1; 
} 
 
 info = g_file_input_stream_query_info（G_FILE_INPUT_STREAM（fis），G_FILE_ATTRIBUTE_STANDARD_SIZE，NULL，& err）; 
 if（info）
 {
 if（g_file_info_has_attribute（info，G_FILE_ATTRIBUTE_STANDARD_SIZE））
 total_size = g_file_info_get_size（info）; 
 printf（total_size =％d \\\
，total_size）; 
 g_object_unref（info）; 
 
 
 //填充缓冲区
 if（total_size> 0）{
 buffer =（char *）malloc（sizeof（char）* total_size）; 
 memset（buffer，0，total_size）; 
 if（（length = g_input_stream_read（G_INPUT_STREAM（fis），
 buffer，total_size，NULL，& err））！= -1）{
 printf（读取文件\ n ）; 
} 
 printf（文件长度=％d \ n，长度）; 
 
 ret = 0; 
} 
 //关闭流
 g_object_unref（fis）; 
 g_object_unref（f）; 
 return ret; 
} 
  

解决方案

HTTP是协议之一由GIO支持，所以在使用GIO功能而不是标准C函数时，您可以像打开任何其他文件一样打开HTTP URI。只需使用 g_file_new_for_uri 创建文件对象，然后您可以像读取本地文件一样读取它。

您可以使用 g_file_read 为给定URI获取一个GFileInputStream，然后为 g_data_input_stream_new 获取输入流的GDataInputStream，然后您可以使用该GDataInputStream逐行读取文件。在将它传递给 g_data_input_stream_new 之前（或者在您可以使用其他任何有用的东西之前），您必须将GFileInputStream转发到GInputStream，但是如果您要将GTK编程为C，你现在可能习惯了。

With what function should I fetch a file from the web using gtk libs?

If my file is from:

gchar *path = "http://xxx.yyyServer/sharing/temp.txt"

What should I do to download it?

For the local files I simply use C libraries like fopen and fread.

How should I do the above?

There is unfortunately no examples of file handling in the Tutorials. I can only see a File chooser from File Dialog boxes.

Please help this noob.

Thanks

UPDATED WITH WORKING CODE FROM COMMENTS: The code below works for binary files of unknown sizes.

char *name= http://127.0.0.1:8000/mybinfile


int getFile(char *name)
{

    GFile *f = g_file_new_for_uri(name);
    GFileInputStream *fis = NULL;
    GDataInputStream* dis = NULL;
    GError *err = NULL;
    //char buffer[2048];
    char *buffer;
    size_t length;
    int ret = -1;

    GFileInfo *info;

    int total_size = -1;

    /* get input stream */
    fis = g_file_read(f, NULL, &err);

    if (err != NULL) {
        fprintf(stderr, "ERROR: opening %s\n", name);
        g_object_unref(f);
        return -1;
    }

    info = g_file_input_stream_query_info (G_FILE_INPUT_STREAM (fis),G_FILE_ATTRIBUTE_STANDARD_SIZE,NULL, &err);
    if (info)
    {
        if (g_file_info_has_attribute (info, G_FILE_ATTRIBUTE_STANDARD_SIZE))
            total_size = g_file_info_get_size (info);
            printf( "total_size = %d\n", total_size);
            g_object_unref (info);
    }

    // fill buffer
    if(total_size > 0){
        buffer = (char *) malloc(sizeof(char) * total_size);
        memset(buffer, 0, total_size);
        if ((length = g_input_stream_read (G_INPUT_STREAM(fis),
                    buffer, total_size, NULL, &err)) != -1) {
                printf( "reading file\n");
        }
        printf( "File length = %d\n", length);

            ret = 0;
        }
        // close streams
        g_object_unref(fis);
        g_object_unref(f);   
        return ret;
    }

解决方案

HTTP is one of the protocols supported by GIO, so you can open an HTTP URI just like any other file when using the GIO functions instead of standard C functions. Just use g_file_new_for_uri to create the file object and then you can read it just like a local file.

You can use g_file_read to get a GFileInputStream for the given URI and then g_data_input_stream_new to get a GDataInputStream for the input stream, which you can then use to read the file line-by-line. You have to upcast the GFileInputStream to a GInputStream before you can pass it to g_data_input_stream_new (or before you can do anything else useful with it), but if you're programming GTK in C, you're probably used to that by now.

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