Anatomy of a request - Revision history

Libjlrs at 21:11, 14 June 2016

2016-06-14T21:11:31Z

Libjlrs: /* Flow of a request */ typo

2015-05-07T09:23:12Z

‎Flow of a request: typo

Libjlrs at 17:20, 28 October 2014

2014-10-28T17:20:18Z

Libjlrs at 13:38, 24 October 2014

2014-10-24T13:38:20Z

Libjlrs at 13:35, 24 October 2014

2014-10-24T13:35:52Z

Libjlrs: /* EPrint IDs, Documents */

2014-10-24T12:20:01Z

‎EPrint IDs, Documents

Libjlrs: /* EPrint IDs, Documents */

2014-10-24T10:23:48Z

‎EPrint IDs, Documents

Libjlrs: /* EPrint IDs, Documents */

2014-10-24T10:03:45Z

‎EPrint IDs, Documents

Libjlrs: Working through Rewrite module

2014-10-23T16:12:46Z

Working through Rewrite module

Libjlrs at 14:05, 13 October 2014

2014-10-13T14:05:04Z

@@ Line 1: / Line 1: @@
 {{AccessControl}}
 This is a description of how EPrints and Apache handles an incoming request.
@@ Line 176: / Line 175: @@
 *DOI - 5 metadata elements
 *40x handling

@@ Line 10: / Line 10: @@
 Below are relevant parts of config files and perl modules that are used with when processing a request.
 The request will generally be dealt with by the <code>EPrints::Apache::Rewrite</code> module, and farmed out from there.
-Hoe the request reaches this module is also explained below.
+How the request reaches this module is also explained below.
 ==Apache core config <code>~/cfg/apache.conf</code>==

@@ Line 7: / Line 7: @@
 I will assume that you know how to locate a perl module file from the module name (e.g. <code>EPrints::Apache::Rewrite</code> will probably be <code>~/perl_lib/EPrints/Apache/Rewrite.pm</code>, although this is not always the case!).
-==Flow of a request==
+=Flow of a request=
 Below are relevant parts of config files and perl modules that are used with when processing a request.
 The request will generally be dealt with by the <code>EPrints::Apache::Rewrite</code> module, and farmed out from there.
 Hoe the request reaches this module is also explained below.
-===Apache core config <code>~/cfg/apache.conf</code>===
+==Apache core config <code>~/cfg/apache.conf</code>==
 <source lang="apache">
@@ Line 23: / Line 23: @@
 See: http://perl.apache.org/docs/2.0/user/handlers/server.html#C_PerlPostConfigHandler_ for more info about the post_config_handler
-===Apache repository config <code>~/cfg/apache/ARCHIVEID.conf</code>===
+==Apache repository config <code>~/cfg/apache/ARCHIVEID.conf</code>==
 <source lang="apache">
 <VirtualHost *:80>
@@ Line 33: / Line 33: @@
 This leads us to the backbone of EPrints - the Rewrite module - where URL_REWRITE_* triggers are called; content negotiation can happen, as well as many other wonderous things!
-===<code>EPrints::Apache::Rewrite</code> module===
+==<code>EPrints::Apache::Rewrite</code> module==
 This explanation, and line numbers are taken from a specific version of the file: https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm Obviously this file will change over time, so it's worth comparing it with the version you are using, and possibly other versions on GitHub e.g. https://github.com/eprints/eprints/blob/3.3/perl_lib/EPrints/Apache/Rewrite.pm
 It's worth taking a few minutes to look at this file - specifically the <code>sub handler</code>.
-====EP_TRIGGER_URL_REWRITE====
+===EP_TRIGGER_URL_REWRITE===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L123 Line 123] calls the 'EP_TRIGGER_URL_REWRITE' trigger:
 <source lang="perl">
@@ Line 55: / Line 55: @@
 [[API:EPrints/Const#:trigger|Information on triggers]]
-====CGI scripts====
+===CGI scripts===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L157 Line 157] deals with CGI scripts - redirecting to HTTPS if necessary. It looks for the CGI scripts in three locations [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L195-199 Lines 195-199]:
 *<code>~/archives/ARCHIVEID/cgi/</code>
@@ Line 72: / Line 72: @@
 </source>
-====SWORD servicedocument====
+===SWORD servicedocument===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L233-258 Lines 233-258] deal with the 'Sword' service document, via the CRUD interface.
-====REST interface====
+===REST interface===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L281-290 Lines 281-290] handle the REST interface, via <code>EPrints::Apache::REST</code>
-====EPrints URIs====
+===EPrints URIs===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L292-374 Lines 292-374]: EPrint URIs are normally of the form <code><nowiki>http://repository.blah/id/...</nowiki></code>. There are three main <code>if</code> blocks in this section that use regex's to match the URI:
 *Line 293 <code>$uri =~ m! ^$urlpath/id/(repository|dump)$ !x</code> matches two cases.
@@ Line 90: / Line 90: @@
 </source>
-====EPrint IDs, Documents and EP_TRIGGER_DOC_URL_REWRITE====
+===EPrint IDs, Documents and EP_TRIGGER_DOC_URL_REWRITE===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L377-493 Lines 377-493] This block of code looks for requests starting with e.g. <code><nowiki>http://repository.blah/123</nowiki></code> - where '123' is an EPrintID.
@@ Line 148: / Line 148: @@
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L470-490 Lines 470-490] If the URL has an EPrint, but doesn't have a document, we reach this block - which updates the abstract page if necessary, and uses the EPrints templating system to render the page. It also logs the page view using <code>EPrints::Apache::LogHandler::eprint</code>.
-====Views====
+===Views===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L504-518 Lines 504-518] handle 'view' requests - and regenerating view pages.
-====auto javascript and css====
+===auto javascript and css===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L519-543 Lines 519-543] deal with generating the 'auto' javascript and css files
-====Other static pages====
+===Other static pages===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L545-560 Lines 545-560] deals with anything else.
-====Other headers====
+===Other headers===
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L562-582 Lines 562-582] set a few headers for specific cases, and also register EPrints::Apache::Template as the handler for any .html files.
 ==TODO (some should be seperate pages)==
 **triggers
 **CRUD
 **???

@@ Line 155: / Line 155: @@
 ====Other static pages====
-[https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L545-560 Lines 545-560] deal with anything else.
+[https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L545-560 Lines 545-560] deals with anything else.
 ====Other headers====

@@ Line 1: / Line 1: @@
 '''THIS PAGE IS UNDER CONSTRUCTION! JLRS 2014-10-23'''
@@ Line 89: / Line 90: @@
 </source>
-====EPrint IDs, Documents ====
+====EPrint IDs, Documents and EP_TRIGGER_DOC_URL_REWRITE====
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L377-493 Lines 377-493] This block of code looks for requests starting with e.g. <code><nowiki>http://repository.blah/123</nowiki></code> - where '123' is an EPrintID.
@@ Line 148: / Line 147: @@
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L470-490 Lines 470-490] If the URL has an EPrint, but doesn't have a document, we reach this block - which updates the abstract page if necessary, and uses the EPrints templating system to render the page. It also logs the page view using <code>EPrints::Apache::LogHandler::eprint</code>.
 ==TODO (some should be seperate pages)==
-*Explain flow of Rewrite
 **triggers
 **content negotiation
 **CRUD
@@ Line 164: / Line 175: @@
 [[Category:EPrints 3.3.12]]

@@ Line 94: / Line 94: @@
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L377-493 Lines 377-493] This block of code looks for requests starting with e.g. <code><nowiki>http://repository.blah/123</nowiki></code> - where '123' is an EPrintID.
 There are some <code>redir</code>ects in this block to account for older URL that may be requested that had EPrintIDs and/or document positions zero-padded <code><nowiki>http://repository.blah/00000123</nowiki></code> or <code><nowiki>http://repository.blah/00000123/01/Document.txt</nowiki></code>.
@@ Line 101: / Line 102: @@
 <source lang="perl">$uri =~ s! ^$urlpath/(0*)([1-9][0-9]*)\b !!x</source>
 will remove the EPrintID from the start of <code>$uri</code>.
 [https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L398 Line 398]
@@ Line 125: / Line 128: @@
 *for each of the split values (referenced as $_): grep for the length of the value. This effectively strips out empty elements (length = 0, grep doesn't return the value).
 *@relationships = <code>"relationship1","relationship2","relationshipN"</code>
 ==TODO (some should be seperate pages)==

@@ Line 115: / Line 115: @@
 </source>
 They deal with document relationships - that are of the form <code>.../DocID.relationship1.relationship2.relationshipN/...</code>.
 For documents, thumbnails are presented as related documents, the relationship is e.g. 'hassmallThumbnailVersion'.
 The first line gets anything from the start of <code>$uri</code> (the DocID already having been removed by line 398), to the next '/'.
 The second line takes the captured match ($1): <code>.relationship1.relationship2.relationshipN</code>
 ==TODO (some should be seperate pages)==

@@ Line 93: / Line 93: @@
 '''Under construction!'''
-[https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L377-493 Lines 377-493] This block of code looks for a request for <code><nowiki>http://repository.blah/123</nowiki></code> - '123' is EPrint ID 123.
+[https://github.com/eprints/eprints/blob/88a36fcf1f17c7a04e60455d374b617709f7461d/perl_lib/EPrints/Apache/Rewrite.pm#L377-493 Lines 377-493] This block of code looks for requests starting with e.g. <code><nowiki>http://repository.blah/123</nowiki></code> - where '123' is an EPrintID.
-$uri =~ s! ^$urlpath/(0*)([1-9][0-9]*)\b !!x
+Each subsequent match on the <code>$uri</code> consumes part of it - e.g.
 ==TODO (some should be seperate pages)==