README - gopherproxy-c - Gopher HTTP proxy in C (CGI)
  HTML git clone git://git.codemadness.org/gopherproxy-c
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       README (3782B)
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            1 gopherproxy
            2 ===========
            3 
            4 Build dependencies
            5 ------------------
            6 
            7 - C compiler.
            8 - libc + some BSD extensions (dprintf).
            9 - POSIX system.
           10 - make (optional).
           11 - LibreSSL libtls for gophers:// support (optional).
           12 
           13 
           14 Features
           15 --------
           16 
           17 - Works in older browsers such as links, lynx, w3m, dillo, etc.
           18 - No Javascript or CSS required.
           19 - Gopher+ is not supported.
           20 - Support for Gopher over TLS encryption (gophers://).
           21 
           22 
           23 Cons
           24 ----
           25 
           26 - Not all gopher types are supported.
           27 
           28 
           29 Gopher over TLS
           30 ---------------
           31 
           32 For a description of the protocol see near the section "TLS support":
           33 gopher://bitreich.org/1/scm/gopher-protocol/file/gopher-extension.md.gph
           34 
           35 For a server implementation see:
           36 - geomyidae: gopher://bitreich.org/1/scm/geomyidae
           37 
           38 For client implementations that support it see:
           39 
           40 - cURL: https://curl.se/
           41 - sacc: gopher://bitreich.org/1/scm/sacc
           42 - hurl: gopher://codemadness.org/1/git/hurl
           43 
           44 
           45 CGI configuration examples
           46 --------------------------
           47 
           48 Nginx + slowcgi:
           49 
           50         location /gopherproxy/ {
           51                 include /etc/nginx/fastcgi_params;
           52                 fastcgi_pass unix:/run/slowcgi.sock;
           53                 fastcgi_param SCRIPT_FILENAME /cgi-bin/gopherproxy.cgi;
           54                 fastcgi_param SCRIPT_NAME     /cgi-bin/gopherproxy.cgi;
           55                 fastcgi_param REQUEST_URI     /cgi-bin/gopherproxy.cgi;
           56         }
           57 
           58 
           59 OpenBSD httpd + slowcgi:
           60 
           61         location "/gopherproxy" {
           62                 root "/cgi-bin/gopherproxy.cgi"
           63                 fastcgi
           64         }
           65 
           66 Caddy + http.cgi:
           67 
           68         proxy.domain.tld {
           69                 cgi /proxy /usr/local/bin/gopherproxy
           70         }
           71 
           72 
           73 Notes
           74 -----
           75 
           76 Restrictions:
           77 
           78 For security reasons, only port 70 and 7070 are accepted as valid gopher ports.
           79 Furthermore there is a connection time limit and download size limit. See the
           80 source-code for more information.
           81 
           82 
           83 Tor support:
           84 
           85 Modify the isblacklisted() function in gopherproxy.c to allow .onion addresses.
           86 
           87 
           88 torsocks support:
           89 
           90 To accept torsocks with gopherproxy, remove the -static flag from LDFLAGS in
           91 the Makefile. This is because torsocks is a shared library and "hooks into" the
           92 network calls.
           93 
           94 
           95 Nginx buffering issues:
           96 
           97 When using nginx 1.12+ with OpenBSD slowcgi there may be buffering issues. This
           98 is a bug in nginx. This bug is fixed in newer nginx versions (see patch below).
           99 
          100 Workaround:
          101         # workaround fastcgi buffering bug in nginx (fixed in 1.14).
          102         fastcgi_buffering off;
          103 
          104 Patch:
          105 
          106 commit cfc8c28259b3fd59f2517ac4830a08e8a9925148
          107 Author: Maxim Dounin <mdounin@mdounin.ru>
          108 Date:   Thu Nov 9 15:35:20 2017 +0300
          109 
          110     FastCGI: adjust buffer position when parsing incomplete records.
          111     
          112     Previously, nginx failed to move buffer position when parsing an incomplete
          113     record header, and due to this wasn't be able to continue parsing once
          114     remaining bytes of the record header were received.
          115     
          116     This can affect response header parsing, potentially generating spurious errors
          117     like "upstream sent unexpected FastCGI request id high byte: 1 while reading
          118     response header from upstream".  While this is very unlikely, since usually
          119     record headers are written in a single buffer, this still can happen in real
          120     life, for example, if a record header will be split across two TCP packets
          121     and the second packet will be delayed.
          122     
          123     This does not affect non-buffered response body proxying, due to "buf->pos =
          124     buf->last;" at the start of the ngx_http_fastcgi_non_buffered_filter()
          125     function.  Also this does not affect buffered response body proxying, as
          126     each input buffer is only passed to the filter once.
          127 
          128 diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
          129 index ea16ecae..b4bb1d0a 100644
          130 --- a/src/http/modules/ngx_http_fastcgi_module.c
          131 +++ b/src/http/modules/ngx_http_fastcgi_module.c
          132 @@ -2646,6 +2646,7 @@ ngx_http_fastcgi_process_record(ngx_http_request_t *r,
          133          }
          134      }
          135  
          136 +    f->pos = p;
          137      f->state = state;
          138  
          139      return NGX_AGAIN;