Apache inets httpd cgi脚本：如何检索json数据？

我尝试的cgi脚本无法从iNet httpd服务器检索json数据

#!/usr/bin/env python3

import json
import sys
import os

content_len = int(os.environ["CONTENT_LENGTH"])

req_body = sys.stdin.read(content_len)
my_dict = json.loads(req_body)

sys.stdout.write("Content-Type: text/html")
sys.stdout.write("\r\n\r\n")

if my_dict:
    a = my_dict.get("a", "Not found")
    b = my_dict.get("b", "Not found")
    total = a + b
    print("<div>Content-Length={}</div".format(content_len))
    print("<div>Got json: {}</div>".format(my_dict) )
    print("<div>a={}, b={}, total={}</div>".format(a, b, total))
else:
    print("<div>Couldn't read json data.</div>")

'''
form = cgi.FieldStorage()

if "a" not in form:
    print("<H1>Error:</H1>")
    print("<div>'a' not in form</div>")
else:
    print("<p>a:{}</p>".format( form["a"].value) )


if "b" not in form:
    print("<H1>Error:</H1>")
    print("<div>'b' not in form</div>")
else:
    print("<p>b:{}</p>".format(form["b"].value) )
'''

为了在cgi脚本中检索json数据，您需要能够读取请求体，其中包含如下内容：

{"a": 1, "b": 2}

使用perl cgi脚本，我可以读取如下请求体：

my $cgi = CGI->new;
my $req_body = $cgi->param('POSTDATA');

我假设这是一种间接读取服务器管道到脚本stdin的方式，因为在python cgi脚本中，我必须编写：

req_body = sys.stdin.read()

当我从apache服务器请求cgi脚本时，我的perl和python cgi脚本可以成功地从apache获取json数据。但是当我从我的

inets-httpd

服务器请求相同的cgi脚本时，我的perl-cgi脚本对请求体不读取任何内容，python-cgi脚本挂起，然后服务器超时。我的cgi脚本能够从

inets httpd

服务器检索格式化为

“a=1&b=2”

的数据——在这种情况下，perl和python中的cgi工具都会自动为我解析数据，因此我不必尝试读取请求体，而只需访问cgi创建的结构

这是我的httpd服务器配置（

server.conf

）：

我用这个程序启动我的httpd服务器（

s.erl

）：

我的cgi脚本（

1.py

）：

在终端窗口中启动服务器：

~/erlang_programs/inets_proj$ erl
Erlang/OTP 20 [erts-9.2] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false]
Eshell V9.2  (abort with ^G)

1> c(s).              
s.erl:2: Warning: export_all flag enabled - all functions will be exported
{ok,s}

2> Server = s:start().
<0.86.0>

3> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {server_name,"httpd_test"},
 {erl_script_nocache,true},
 {script_alias,{"/cgi-bin/",
                "/Users/7stud/erlang_programs/inets_proj/cgi-bin/"}},
 {bind_address,{127,0,0,1}},
 {modules,[mod_alias,mod_actions,mod_esi,mod_cgi,mod_get,
           mod_log]},
 {server_root,"/Users/7stud/erlang_programs/inets_proj"},
 {erl_script_alias,{"/erl",[mymod]}},
 {port,51301},
 {transfer_log,<0.93.0>},
 {error_log,<0.92.0>},
 {document_root,"./htdocs"}]
4> 

---

我找到了cgi规范的RFC，上面写着：

RFC 3875                    CGI Version 1.1                 October 2004


4.2.  Request Message-Body

   Request data is accessed by the script in a system-defined method;
   unless defined otherwise, this will be by reading the 'standard
   input' file descriptor or file handle.

      Request-Data   = [ request-body ] [ extension-data ]
      request-body   = <CONTENT_LENGTH>OCTET
      extension-data = *OCTET

   A request-body is supplied with the request if the CONTENT_LENGTH is
   not NULL.  The server MUST make at least that many bytes available
   for the script to read.  The server MAY signal an end-of-file
   condition after CONTENT_LENGTH bytes have been read or it MAY supply
   extension data.  Therefore, the script MUST NOT attempt to read more
   than CONTENT_LENGTH bytes, even if more data is available.  However,
   it is not obliged to read any of the data.

我无法让perl的CGI模块与从STDIN读取一起工作编辑：帕尔蒙克斯的一位善良的灵魂帮助我解决了这个问题：

my $q = CGI->new('');

空白字符串告诉CGI->new不要从stdin读取并解析数据

~/erlang_programs/inets_proj$ erl
Erlang/OTP 20 [erts-9.2] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false]
Eshell V9.2  (abort with ^G)

1> c(s).              
s.erl:2: Warning: export_all flag enabled - all functions will be exported
{ok,s}

2> Server = s:start().
<0.86.0>

3> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {server_name,"httpd_test"},
 {erl_script_nocache,true},
 {script_alias,{"/cgi-bin/",
                "/Users/7stud/erlang_programs/inets_proj/cgi-bin/"}},
 {bind_address,{127,0,0,1}},
 {modules,[mod_alias,mod_actions,mod_esi,mod_cgi,mod_get,
           mod_log]},
 {server_root,"/Users/7stud/erlang_programs/inets_proj"},
 {erl_script_alias,{"/erl",[mymod]}},
 {port,51301},
 {transfer_log,<0.93.0>},
 {error_log,<0.92.0>},
 {document_root,"./htdocs"}]
4> 

$ curl -v \
> -H 'Content-Type: application/json' \
> --data '{"a": 1, "b": 2}' \
> http://localhost:51301/cgi-bin/1.py

*   Trying ::1...
* TCP_NODELAY set
* Connection failed
* connect to ::1 port 51301 failed: Connection refused
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 51301 (#0)
> POST /cgi-bin/1.py HTTP/1.1
> Host: localhost:51301
> User-Agent: curl/7.58.0
> Accept: */*
> Content-Type: application/json
> Content-Length: 16
> 
* upload completely sent off: 16 out of 16 bytes

===== hangs for about 5 seconds ====

< HTTP/1.1 504 Gateway Time-out
< Date: Thu, 08 Mar 2018 11:02:27 GMT
< Content-Type: text/html
< Server: inets/6.4.5
* no chunk, no close, no size. Assume close to signal end
< 
* Closing connection 0
$ 

~/erlang_programs$ tree inets_proj/
inets_proj/
├── apache_cl.erl
├── cgi-bin
│   ├── 1.pl
│   └── 1.py
├── cl.beam
├── cl.erl
├── errors.log
├── htdocs
│   └── file1.txt
├── mylog.log
├── mymod.beam
├── mymod.erl
├── old_server.conf
├── old_server3.conf
├── old_server4.conf
├── requests.log
├── s.beam
├── s.erl
├── server.conf
└── urlencoded_post_cl.erl

RFC 3875                    CGI Version 1.1                 October 2004


4.2.  Request Message-Body

   Request data is accessed by the script in a system-defined method;
   unless defined otherwise, this will be by reading the 'standard
   input' file descriptor or file handle.

      Request-Data   = [ request-body ] [ extension-data ]
      request-body   = <CONTENT_LENGTH>OCTET
      extension-data = *OCTET

   A request-body is supplied with the request if the CONTENT_LENGTH is
   not NULL.  The server MUST make at least that many bytes available
   for the script to read.  The server MAY signal an end-of-file
   condition after CONTENT_LENGTH bytes have been read or it MAY supply
   extension data.  Therefore, the script MUST NOT attempt to read more
   than CONTENT_LENGTH bytes, even if more data is available.  However,
   it is not obliged to read any of the data.

#!/usr/bin/env python3

import json
import sys
import os

content_len = int(os.environ["CONTENT_LENGTH"])

req_body = sys.stdin.read(content_len)
my_dict = json.loads(req_body)

sys.stdout.write("Content-Type: text/html")
sys.stdout.write("\r\n\r\n")

if my_dict:
    a = my_dict.get("a", "Not found")
    b = my_dict.get("b", "Not found")
    total = a + b
    print("<div>Content-Length={}</div".format(content_len))
    print("<div>Got json: {}</div>".format(my_dict) )
    print("<div>a={}, b={}, total={}</div>".format(a, b, total))
else:
    print("<div>Couldn't read json data.</div>")

'''
form = cgi.FieldStorage()

if "a" not in form:
    print("<H1>Error:</H1>")
    print("<div>'a' not in form</div>")
else:
    print("<p>a:{}</p>".format( form["a"].value) )


if "b" not in form:
    print("<H1>Error:</H1>")
    print("<div>'b' not in form</div>")
else:
    print("<p>b:{}</p>".format(form["b"].value) )
'''

4> httpd:info(Server).
[{mime_types,[{"htm","text/html"},{"html","text/html"}]},
 {server_name,"httpd_test"},
 {erl_script_nocache,true},
 {script_alias,{"/cgi-bin/",
                "/Users/7stud/erlang_programs/inets_proj/cgi-bin/"}},
 {bind_address,{127,0,0,1}},
 {modules,[mod_alias,mod_actions,mod_esi,mod_cgi,mod_get,
           mod_log]},
 {server_root,"/Users/7stud/erlang_programs/inets_proj"},
 {erl_script_alias,{"/erl",[mymod]}},
 {port,65451},
 {transfer_log,<0.93.0>},
 {error_log,<0.92.0>},
 {document_root,"./htdocs"}]
5> 

~$ curl -v \
> -H 'Content-Type: application/json' \
> --data '{"a": 1, "b": 2}' \
> http://localhost:65451/cgi-bin/1.py

*   Trying ::1...
* TCP_NODELAY set
* Connection failed
* connect to ::1 port 65451 failed: Connection refused
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 65451 (#0)
> POST /cgi-bin/1.py HTTP/1.1
> Host: localhost:65451
> User-Agent: curl/7.58.0
> Accept: */*
> Content-Type: application/json
> Content-Length: 16
> 
* upload completely sent off: 16 out of 16 bytes
< HTTP/1.1 200 OK
< Date: Fri, 09 Mar 2018 04:36:42 GMT
< Server: inets/6.4.5
< Transfer-Encoding: chunked
< Content-Type: text/html
< 
<div>Content-Length=16</div
<div>Got json: {'a': 1, 'b': 2}</div>
<div>a=1, b=2, total=3</div>
* Connection #0 to host localhost left intact
~$ 

#!/usr/bin/env perl

use strict;
use warnings;
use 5.020;
use autodie;
use Data::Dumper;
use JSON;

if (my $content_len = $ENV{CONTENT_LENGTH}) {

    read(STDIN, my $json, $content_len);
    my $href = decode_json($json);
    my $a = $href->{a};
    my $b = $href->{b};

    print 'Content-type: text/html';
    print "\r\n\r\n";
    print "<div>a=$a</div>";
    print "<div>b=$b</div>";

    #my $q = CGI->new; #Doesn't work with inets httpd server
    #my $q = CGI->new(''); #Doesn't try to read from stdin, do does work.

    #  print $q->header,
    #    $q->start_html("Test Page"),
    #    $q->div("json=$json"),
    #    $q->div("a=$a"),
    #    $q->div("b=$b"),
    #    $q->div("total=$total"),
    #    $q->end_html;
} 
else {
    my $error = "Could not read json: No Content-Length header in request.";
    print 'Content-type: text/html';
    print "\r\n\r\n";
    print "<div>$error</div>";


    #   my $q = CGI->new;
    #   print $q->header,
    #         $q->start_html("Test Page"),
    #         $q->h1($error),
    #         $q->end_html;
}

my $q = CGI->new('');