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While the SCGI protocol insulates the service programmer from some HTTP considerations, various details (such as interpreting the octets of the message body as per the
Transfer-Encoding header, the CONTENT_LENGTH being the number of octets after the body has been encoded for transmission, etc.) still
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Duplicate names are not allowed in the request headers; RFC 2616-compliant header combining must already have taken place. The first request header must have the name "CONTENT_LENGTH" and a value that is the length of the body in decimal. The "CONTENT_LENGTH" request header must always be present,
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The client connects to a SCGI server over a reliable stream protocol allowing transmission of 8-bit bytes. The client begins by sending a request. When the SCGI server sees the end of the request it sends back a response and closes the connection. The format of the response is not specifically
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between a web server and an application server. This is in contrast to CGI, which is an earlier application (gateway) interface designed to let the application programmer avoid the complexity of sockets and long-running service processes when poor scalability and high overhead are acceptable.
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The SCGI protocol leverages the fact that the web server has already parsed and validated the HTTP request, and canonically communicates the request to the SCGI server while letting the application programmer avoid parsing ambiguities and protocol edge cases. This avoids the complicated
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but is designed to be easier to parse. Unlike CGI, it permits a long-running service process to continue serving requests, thus avoiding delays in responding to requests due to setup overhead (such as connecting to a database).
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should be provided in SCGI headers for compatibility when converting older CGI programs to SCGI. The body (if any) provided in the request follows the headers; its length is specified by the "CONTENT_LENGTH" request header.
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Neil
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The web server (a SCGI client) opens a connection and sends the concatenation of the following strings to the service process (a SCGI server):
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even if its value is "0". There must also always be a request header with the name "SCGI" and a value of "1". Standard CGI
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header-parsing and header-combining rules from RFC 2616, saving significant complexity in the SCGI server process.
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The specification document was placed in the public domain by Neil
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specified by this protocol, although CGI-equivalent HTTP responses are generally used.
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The SCGI server sends the following response back to the web server:
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SCGI can be implemented in any language that supports
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require knowledge of the HTTP protocol specification.
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272:Comparison of web server software § Features
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113:Learn how and when to remove this message
202:, where both the name and the value are
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484:Application hosts (language-specific):
262:The SCGI server closes the connection.
574:Schemenauer, Neil (October 30, 2001).
468:- Launches a child process per request
598:MNX: MEMS and Nanotechnology Exchange
225:to form a single byte sequence, then
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51:adding citations to reliable sources
616:"Althttpd: The Althttpd Webserver"
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317:Language bindings for the SCGI API
137:servers, as an alternative to the
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596:. Index of /software/files/scgi.
62:"Simple Common Gateway Interface"
600:. April 12, 2002. Archived from
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552:For HTTP header combining, see
461:Application/Gateway protocols:
266:Web servers that implement SCGI
127:Simple Common Gateway Interface
38:needs additional citations for
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466:Common Gateway Interface(CGI)
299:Internet Information Services
525:web server gateway interface
515:Web Server Gateway Interface
505:Web Server Gateway Interface
658:SCGI protocol specification
277:(this list is not complete)
141:protocol. It is similar to
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198:Each header consists of a
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221:All provided headers are
210:). The value can be an
204:null-terminated strings
187:A SCGI request is the
478:Apache JServ Protocol
235:environment variables
18:San Guillermo Airport
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303:ISAPI SCGI extension
47:improve this article
554:RFC2616 section 4.2
980:Application server
283:Apache HTTP Server
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1266:Web SQL Database
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638:External links
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604:on 2002-10-20.
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183:Request format
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64: –
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58:Find sources:
52:
48:
42:
41:
36:This article
34:
30:
25:
24:
19:
1015:Browser APIs
956:Web resource
750:
623:. Retrieved
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602:the original
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588:
580:the original
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380:or with the
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276:
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223:concatenated
220:
212:empty string
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130:
126:
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109:
103:October 2017
100:
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69:
57:
45:Please help
40:verification
37:
1394:Progressive
1389:Single-page
1197:WebAssembly
1177:Geolocation
1134:Web storage
1040:C NPRuntime
1028:LiveConnect
1006:Client-side
952:Web service
881:mod_include
836:Python ASGI
831:Python WSGI
781:Server APIs
702:Server-side
433:, with the
418:, with the
398:package or
394:, with the
376:, with the
361:, with the
351:, with the
341:, with the
1162:DOM events
1139:Web worker
1124:WebSockets
985:comparison
921:mod_python
901:mod_parrot
734:Encryption
620:sqlite.org
561:References
523:JavaScript
435:tokio-scgi
349:Emacs Lisp
327:netstrings
297:Microsoft
270:See also:
216:null bytes
149:SCGI is a
73:newspapers
1320:Scripting
1182:IndexedDB
1033:XPConnect
992:Scripting
916:mod_proxy
861:container
851:Perl PSGI
841:Ruby Rack
814:container
771:WebSocket
711:Protocols
402:framework
227:netstring
208:C strings
193:netstring
1416:Category
1345:Web page
1202:WebAuthn
1077:Web APIs
970:Open API
931:mod_ruby
926:mod_wsgi
906:mod_perl
896:mod_mono
891:mod_lisp
821:CLI OWIN
457:See also
353:url-scgi
343:arsd.cgi
312:Althttpd
293:Lighttpd
288:Cherokee
151:protocol
1355:Dynamic
1315:Web IDL
1261:GraphQL
1227:Khronos
1057:ActiveX
1045:C PPAPI
1023:C NPAPI
975:Webhook
911:mod_php
856:Portlet
804:COM ASP
799:C ISAPI
794:C ASAPI
789:C NSAPI
472:FastCGI
422:library
383:library
369:Haskell
365:package
355:library
345:library
246:Example
166:History
143:FastCGI
87:scholar
1350:Static
1333:Topics
1310:Mashup
1285:Topics
1272:WebUSB
1249:Others
1212:WebRTC
1207:WebGPU
1099:Canvas
1086:WHATWG
945:Topics
886:mod_jk
739:WebDAV
625:19 May
513:Python
441:Scheme
416:Racket
411:Python
89:
82:
75:
68:
60:
1300:DHTML
1256:Gears
1240:WebGL
1235:WebCL
1217:WebXR
1119:Video
1094:Audio
530:Notes
437:crate
400:Plack
334:Cobra
308:nginx
301:with
94:JSTOR
80:books
1384:Rich
1367:REST
1298:vs.
1294:and
1292:Ajax
1172:File
1104:CORS
1067:XBAP
1050:NaCl
963:vs.
954:vs.
766:WSRP
756:FCGI
751:SCGI
719:HTTP
627:2023
519:JSGI
509:WSGI
503:Perl
499:PSGI
493:Ruby
489:Rack
431:Rust
426:Ruby
420:scgi
396:SCGI
392:Perl
387:Lisp
374:Java
363:scgi
325:and
135:HTTP
131:SCGI
125:The
66:news
1192:SVG
1187:MSE
1167:EME
1154:W3C
1114:SSE
1109:DOM
1062:BHO
965:ROA
961:WOA
761:AJP
746:CGI
451:Nim
446:Tcl
406:PHP
191:of
139:CGI
49:by
1418::
729:v3
724:v2
618:.
545:2.
535:1.
521:–
511:-
501:-
491:-
359:Go
686:e
679:t
672:v
629:.
556:.
339:D
206:(
129:(
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110:(
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101:(
91:·
84:·
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70:·
43:.
20:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
