• 利用CGI (C)及HTML实现PC本地文件的上传功能

    背景：设备端（采集端） + 云端（服务端）+ 浏览端（客户端）这种结构是比较常见的，而在某些情形，云端如果涉及到跨境跨域的问题，上述的架构就不一定合适。在功能要求不是那么复杂的情况下，可以考虑设备端（采集端+服务端）+ 浏览端（客户端）这种架构。在设备端移植搭建服务器，并将显示的相关html文件部署其上，浏览器输入设备地址及html文件名，即可实现远程监控功能。

    功能：点击网页上文件选择按钮，从本地选择待上传的文件，完成后点击上传按钮，将选中的文件上传到web server。

    HTML内容如下

    例子一：

    1. html>
    2. <html>
    3. <head>
    4.     <title>文件上传title>
    5. head>
    6. <body>
    7.     <form action="/cgi-bin/upload.cgi" enctype="multipart/form-data" method="post"> 
    8.     <table>                             
    9. 	<tbody>
    10. 	<tr>
    11. 	    <td> upload file td>
    12. 	    <td><input type="file" name="uploadfile" value="">td>
    13. 	    <td><input type="submit" name="upload" value="上传">td>
    14. 	tr>
    15.     tbody>
    16.     table>
    17. form>
    18. body>
    19. html>

    例子二(网友方案)：

    1. html>
    2. <html>
    3. 	<style>
    4. 		body
    5. 		{
    6. 			background-color: lightblue;
    7. 		}
    8. 		div
    9. 		{
    10. 			margin-left: 30px;
    11. 			margin-top: 30px;
    12. 		}
    13. 	style>
    14.     <head>
    15. 		<meta charset="utf-8">
    16.         <title>Upload File Testtitle>
    17.     head>
    18. 	
    19.     <body>
    20.         <form enctype='multipart/form-data' action="/cgi-bin/upload.cgi" method="post">
    21. 			<div>
    22. 				<span>上传路径：span><input type="text" name="updatapath" value="/tmp/">
    23. 			div>
    24.             <div>
    25. 				<input type="file" name='updatafile' multiple>
    26. 			div>
    27.             <div>
    28. 				<input type="submit" value="确认上传">
    29. 			div>
    30.         
    31.     body>
    32. html>

    上传文件功能必须开启

    enctype="multipart/form-data" method="post"

    CGI C实现：

    例子一配套C代码：

    1. #include 
    2. #include 
    3. #include 
    4. #include "cgic.h"
    5.  
    6. enum ErrLog
    7. {
    8.     ErrSucceed,
    9.     ErrOpenFile,
    10.     ErrNoFile
    11. };
    12. enum ErrLog UploadFile()
    13. {
    14.     cgiFilePtr file;
    15.     FILE *fd;
    16.     char name[512];
    17.     char path[128];
    18.     char contentType[1024];
    19.     int size = 0;
    20.     int got = 0;
    21.     int t = 0;
    22.     char *tmp = NULL;
    23.  
    24. 	cgiHeaderContentType("text/html; charset=utf-8");
    25. 	
    26. 	cgiFormResultType ret;
    27. 	ret = cgiFormFileName("uploadfile", name, sizeof(name));
    28. 	switch(ret)
    29. 	{
    30. 		case cgiFormNotFound:
    31. 			printf("
      cgiFormNotFound. 
      \n"      );
    32. 			break;
    33. 		case cgiFormTruncated:
    34. 			printf("
      cgiFormTruncated. 
      \n"      );
    35. 			break;
    36. 		case cgiFormSuccess:
    37. 			printf("
      cgiFormSuccess. 
      \n"      );
    38. 			break;
    39. 		default:
    40. 			printf("
      unknown. 
      \n"      );
    41. 			break;
    42. 	}
    43.     if (ret != cgiFormSuccess) //获取客户端pathname 
    44.     {
    45.         printf("
      %s No file was uploaded. 
      \n"      , name);
    46.         return ErrNoFile;
    47.     }
    48.     fprintf(cgiOut, "The filename submitted was: ");
    49.     cgiHtmlEscape(name);
    50.     fprintf(cgiOut, "
      \n"      );
    51. 	
    52.     cgiFormFileSize("uploadfile", &size);
    53.     fprintf(cgiOut, "The file size was: %d bytes
      \n"      , size);
    54. 	
    55.     cgiFormFileContentType("uploadfile", contentType, sizeof(contentType));
    56.     fprintf(cgiOut, "The alleged content type of the file was: ");
    57.     cgiHtmlEscape(contentType);
    58.     fprintf(cgiOut, "
      \n"      );
    59.  
    60.     if (cgiFormFileOpen("uploadfile", &file) != cgiFormSuccess)  //尝试打开上传的，并存放在系统中的临时文件
    61.     {
    62.         fprintf(cgiOut, "
       Could not open the file. 
      \n"      );
    63.         return ErrOpenFile;
    64.     }
    65.  
    66.     t = -1;
    67.     while (1)
    68.     {
    69.         tmp = strstr(name+t+1, "\\");  // 从pathname解析出filename
    70.         if (NULL == tmp)
    71.         {
    72.             tmp = strstr(name+t+1, "/");
    73.         }
    74.         if (NULL != tmp)
    75.         {
    76.             t = (int)(tmp-name);
    77.         }
    78.         else
    79.         {
    80.             break;
    81.         }
    82.     }
    83.     tmp = (char *)malloc(size * sizeof(char)); // 在底层建立新文件
    84.     strcpy(path, "/tmp/"); // 路径最后一个字符必须是'/'，否则最终的文件（带路径）将会不知道写到什么地方去了
    85.     strcat(path, name+t+1);  
    86.     fd = fopen(path, "wb");
    87.     if (fd == NULL)
    88.     {
    89.         return ErrOpenFile;
    90.     }
    91.  
    92.     while (cgiFormFileRead(file, tmp, size, &got) == cgiFormSuccess) // 从临时文件读出content
    93.     {
    94.         fwrite(tmp, size, sizeof(char), fd);  //把读出的content写入新文件
    95.     }
    96.     fprintf(cgiOut, "
       Upload File Success. 
      \n"      );
    97.  
    98.     cgiFormFileClose(file);
    99.     free(tmp);
    100.     fclose(fd);
    101.     return ErrSucceed;
    102. }
    103.  
    104. int cgiMain()
    105. {		
    106. 	return UploadFile();
    107. 	
    108. }

    例子二配套C代码（网友方案，借鉴于CGI提供的cgitest.c例子，里面涉及到CGI的各种特性）：

    1. /* Change this if the SERVER_NAME environment variable does not report
    2. 	the true name of your web server. */
    3. #if 1
    4. #define SERVER_NAME cgiServerName
    5. #endif
    6. #if 0
    7. #define SERVER_NAME "www.boutell.dev"
    8. #endif
    9.  
    10. /* You may need to change this, particularly under Windows;
    11. 	it is a reasonable guess as to an acceptable place to
    12. 	store a saved environment in order to test that feature. 
    13. 	If that feature is not important to you, you needn't
    14. 	concern yourself with this. */
    15.  
    16. #include 
    17. #include 
    18. #include 
    19. #include 
    20. #include 
    21. #include 
    22. #include 
    23. #include 
    24. #include "cgic.h"
    25.  
    26. //#define DEBUG_ON
    27. #ifdef DEBUG_ON
    28. void PrintMessage(const char *str)
    29. {
    30.     int fd;
    31.     fd =  open("/home/vmuser/mycgi_log",O_WRONLY|O_CREAT|O_APPEND);
    32.     if(fd < 0)
    33.         return;
    34.  
    35.     time_t the_time;
    36.  
    37.     struct tm *info;
    38.     time(&the_time);
    39.     info = gmtime(&the_time );
    40.  
    41.     dprintf(fd,"[%2d:%02d]\n", (info->tm_hour)%24, info->tm_min);
    42.  
    43.     write(fd,str,strlen(str));
    44.  
    45.     close(fd);
    46.  
    47. }
    48. #endif
    49.  
    50.  
    51. enum ErrLog
    52. {
    53.     ErrSucceed = 0x00,
    54.     ErrOpenFile,
    55.     ErrNoFile,
    56.     ErrNonePath
    57. };
    58.  
    59. int cgiMain() {
    60.  
    61.         cgiFilePtr file;
    62.         FILE *fd;
    63.         char name[512];
    64.         char path[128];
    65.         char contentType[1024];
    66.         int size = 0;
    67.         int got = 0;
    68.         int t = 0;
    69.         char *tmp = NULL;
    70.  
    71.         //设置类型文件
    72.         cgiHeaderContentType("text/html; charset=utf-8");
    73.         if (cgiFormFileName("updatafile", name, sizeof(name)) != cgiFormSuccess) //获取客户端pathname
    74.         {
    75.            fprintf(cgiOut,"
       文件上传失败. 
      \n"      );
    76.            return ErrNoFile;
    77.         }
    78.  
    79.         //显示上传文件内容
    80.         fprintf(cgiOut, "提交上传文件名称: ");
    81.         cgiHtmlEscape(name);//虽然已经获取到名称，如果文件名中有特殊的名称，将会被转换，总结：从html获取的字符串需要显示到网页的用这个比较好，用fprintf也可以。
    82.         fprintf(cgiOut, "
      \n"      );
    83.  
    84.         //获取文件大小
    85.         cgiFormFileSize("updatafile", &size);
    86.         fprintf(cgiOut, "文件大小为: %d 字节
      \n"      , size);
    87.  
    88.         //上传文件内容类型
    89.         cgiFormFileContentType("updatafile", contentType, sizeof(contentType));
    90.         fprintf(cgiOut, "文件的内容类型为: ");
    91.         cgiHtmlEscape(contentType);
    92.         fprintf(cgiOut, "
      \n"      );
    93.  
    94.         if (cgiFormString("updatapath", path, sizeof (path)) != cgiFormSuccess)
    95.         {
    96.             fprintf(cgiOut, "
       Could not open the file. 
      \n"      );
    97.             return ErrNonePath;
    98.         }
    99.  
    100.         //上传文件内容类型
    101.         fprintf(cgiOut, "文件的路径: ");
    102.         cgiHtmlEscape(path);
    103.         fprintf(cgiOut, "
      \n"      );
    104.  
    105.         //尝试打开上传的，并存放在系统中的临时文件
    106.         if (cgiFormFileOpen("updatafile", &file) != cgiFormSuccess)
    107.         {
    108.            fprintf(cgiOut, "
       Could not open the file. 
      \n"      );
    109.            return ErrOpenFile;
    110.         }
    111.  
    112.         t = -1;
    113.         while (1)
    114.         {
    115.            tmp = strstr(name+t+1, "\\");  // 从pathname解析出filename
    116.            if (NULL == tmp)
    117.                tmp = strstr(name+t+1, "/");
    118.            if (NULL != tmp)
    119.                t = (int)(tmp-name);
    120.            else
    121.                break;
    122.         }
    123. 		//动态内存分配
    124.         tmp = (char *)malloc(size * sizeof(char)); 
    125.         strcat(path, name+t+1);
    126.  
    127.         //上传文件内容类型
    128.         fprintf(cgiOut, "最终生成文件: ");
    129.         cgiHtmlEscape(path);
    130.         fprintf(cgiOut, "
      \n"      );
    131.  
    132.  
    133.         //创建文件，以字节流的方式打开
    134.         fd = fopen(path, "wb+");
    135.         if (fd == NULL)
    136.         {
    137.            return ErrOpenFile;
    138.         }
    139.  
    140.         // 从临时文件读出content
    141.         while (cgiFormFileRead(file, tmp, size, &got) == cgiFormSuccess)
    142.         {
    143.            fwrite(tmp, size, sizeof(char), fd);  //把读出的content写入新文件
    144.         }
    145.  
    146.         //打印输出
    147.         fprintf(cgiOut, "
       上传文件成功. 
      \n"      );
    148.  
    149.         //关闭文件
    150.         cgiFormFileClose(file);
    151.         free(tmp);
    152.         fclose(fd);
    153.  
    154. 		//跳转回到主页面，这个需要浏览器html代码功能来实现
    155.         //fprintf(cgiOut,"");
    156.         return ErrSucceed;
    157.  
    158.  
    159. }

            上述CGI程序的编译需要注意一点，一般有cgiMain（及其他CGI的API）需要链接静态库（或直接带上cgic.c，同样性质），比如最终编译生成的目标文件为upload.cgi，则可按照下面的语句进行编译：

    1. 交叉编译工具链按实际使用的来，下述只是示例。
    2.  
    3. 方式一：
    4. arm-linux-gcc -o upload.cgi upload.c -L ./-lcgic
    5.  
    6. 方式二：
    7. arm-linux-gcc -o upload.cgi upload.c cgic.c

            前期曾尝试直接通过html + js实现文件的上传功能，以期省点空间，无奈出现过4xx、3xx错误，解决了后还是没有上传成功，有知晓的同学还望指点一二。

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  • 原文地址：https://blog.csdn.net/DIANZI520SUA/article/details/133293716