分析FastCGI源码目录下example中echo.c代码：
1 /* 2 * echo.c -- 3 * 4 * Produce a page containing all FastCGI inputs 5 * 6 * 7 * Copyright (c) 1996 Open Market, Inc. 8 * 9 * See the file "LICENSE.TERMS" for information on usage and redistribution 10 * of this file, and for a DISCLAIMER OF ALL WARRANTIES. 11 * 12 */ 13 #ifndef lint 14 static const char rcsid[] = "$Id: echo.c,v 1.5 1999/07/28 00:29:37 roberts Exp $"; 15 #endif /* not lint */ 16 17 #include "fcgi_config.h" 18 19 #include <stdlib.h> 20 21 #ifdef HAVE_UNISTD_H 22 #include <unistd.h> 23 #endif 24 25 #ifdef _WIN32 26 #include <process.h> 27 #else 28 extern char **environ; 29 #endif 30 31 #include "fcgi_stdio.h" 32 33 //输出环境变量 34 static void PrintEnv(char *label, char **envp) 35 { 36 printf("%s:<br> <pre> ", label); 37 for ( ; *envp != NULL; envp++) { 38 printf("%s ", *envp); 39 } 40 printf("</pre><p> "); 41 } 42 43 int main () 44 { 45 //environ 是指向环境变量 字符串数组（全局指针） 46 //保存初始状态下的环境变量执政 47 char **initialEnv = environ; 48 int count = 0; //计数 49 50 //阻塞点，有请求来 FCGI_Accept 就返回 51 while (FCGI_Accept() >= 0) { 52 //获取 CONTENT_LENGTH 环境变量的值 53 char *contentLength = getenv("CONTENT_LENGTH"); 54 int len; 55 56 printf("Content-type: text/html " 57 " " 58 "<title>FastCGI echo</title>" 59 "<h1>FastCGI echo</h1> " 60 "Request number %d, Process ID: %d<p> ", ++count, getpid()); 61 62 if (contentLength != NULL) { 63 //string 转 long 64 len = strtol(contentLength, NULL, 10); 65 } 66 else { 67 len = 0; 68 } 69 70 if (len <= 0) { 71 printf("No data from standard input.<p> "); 72 } 73 else { 74 int i, ch; 75 76 printf("Standard input:<br> <pre> "); 77 for (i = 0; i < len; i++) { 78 if ((ch = getchar()) < 0) { 79 printf("Error: Not enough bytes received on standard input<p> "); 80 break; 81 } 82 putchar(ch); 83 } 84 printf(" </pre><p> "); 85 } 86 87 //打印环境变量 88 PrintEnv("Request environment", environ); 89 PrintEnv("Initial environment", initialEnv); 90 } /* while */ 91 92 return 0; 93 }
访问web服务器后的页面显示信息：
http://192.168.1.45/login?user=citrus&passwd=123456
http请求头的 key 和最后拿到的环境变量的 key 对应关系保存在 nginx fastcgi.conf 文件里面。
FastCGI echo Request number 1, Process ID: 58012 No data from standard input. Request environment: FCGI_ROLE=RESPONDER SCRIPT_FILENAME=/usr/local/nginx/html/login QUERY_STRING=user=citrus&passwd=123456 REQUEST_METHOD=GET CONTENT_TYPE= CONTENT_LENGTH= SCRIPT_NAME=/login REQUEST_URI=/login?user=citrus&passwd=123456 DOCUMENT_URI=/login DOCUMENT_ROOT=/usr/local/nginx/html SERVER_PROTOCOL=HTTP/1.1 REQUEST_SCHEME=http GATEWAY_INTERFACE=CGI/1.1 SERVER_SOFTWARE=nginx/1.13.10 REMOTE_ADDR=192.168.1.119 REMOTE_PORT=60974 SERVER_ADDR=192.168.1.45 SERVER_PORT=80 SERVER_NAME=localhost REDIRECT_STATUS=200 HTTP_ACCEPT=text/html, application/xhtml+xml, image/jxr, */* HTTP_ACCEPT_LANGUAGE=zh-CN HTTP_ACCEPT_ENCODING=gzip, deflate HTTP_HOST=192.168.1.45 HTTP_CONNECTION=Keep-Alive HTTP_USER_AGENT=Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko Core/1.70.3741.400 QQBrowser/10.5.3863.400 Initial environment:
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