Changes between Version 2 and Version 3 of TracModWSGI


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Timestamp:
Aug 13, 2018, 11:36:55 AM (6 years ago)
Author:
trac
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  • TracModWSGI

    v2 v3  
    1 = Trac and mod_wsgi =
    2 
    3 
    4 [http://code.google.com/p/modwsgi/ mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of the Apache webserver. The mod_wsgi adapter is written completely in C and provides very good performance.
     1= Trac and mod_wsgi
     2
     3[https://github.com/GrahamDumpleton/mod_wsgi mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of the Apache webserver. The mod_wsgi adapter is written completely in C and provides very good performance.
    54
    65[[PageOutline(2-3,Overview,inline)]]
    … …  
    87== The `trac.wsgi` script
    98
    10 Trac can be run on top of mod_wsgi with the help of the following application script, which is just a Python file, though usually saved with a `.wsgi` extension).
     9Trac can be run on top of mod_wsgi with the help of an application script, which is a Python file saved with a `.wsgi` extension.
     10
     11A robust and generic version of this file can be created using the `trac-admin <env> deploy <dir>` command which automatically substitutes the required paths, see TracInstall#cgi-bin. The script should be sufficient for most installations and users not wanting more information can proceed to [#Mappingrequeststothescript configuring Apache].
     12
     13If you are using Trac with multiple projects, you can specify their common parent directory using the `TRAC_ENV_PARENT_DIR` in trac.wsgi:
     14{{{#!python
     15def application(environ, start_request):
     16    # Add this to config when you have multiple projects
     17    environ.setdefault('trac.env_parent_dir', '/usr/share/trac/projects') 
     18    ..
     19}}}
    1120
    1221=== A very basic script
     22
    1323In its simplest form, the script could be:
    1424
    … …  
    2333}}}
    2434
    25 The `TRAC_ENV` variable should naturally be the directory for your Trac environment (if you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead), while the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs.
     35The `TRAC_ENV` variable should naturally be the directory for your Trac environment, and the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs. If you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead of `TRAC_ENV`.
    2636
    2737On Windows:
    … …  
    3040os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
    3141}}}
    32  - If run under a Window service, you should create a directory for Python Egg cache.
     42 - If run under a Window service, you should create a directory for Python Egg cache:
    3343{{{#!python
    3444os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
    … …  
    3747=== A more elaborate script
    3848
    39 If you're using multiple `.wsgi` files (for example one per Trac environment) you must ''not'' use `os.environ['TRAC_ENV']` to set the path to the Trac environment. Using this method may lead to Trac delivering the content of another Trac environment, as the variable may be filled with the path of a previously viewed Trac environment.
     49If you are using multiple `.wsgi` files (for example one per Trac environment) you must ''not'' use `os.environ['TRAC_ENV']` to set the path to the Trac environment. Using this method may lead to Trac delivering the content of another Trac environment, as the variable may be filled with the path of a previously viewed Trac environment.
    4050
    4151To solve this problem, use the following `.wsgi` file instead:
    … …  
    5363For clarity, you should give this file a `.wsgi` extension. You should probably put the file in its own directory, since you will expose it to Apache.
    5464
    55 If you have installed Trac and eggs in a path different from the standard one you should add that path by adding the following code at the top of the wsgi script:
     65If you have installed Trac and Python eggs in a path different from the standard one, you should add that path by adding the following code at the top of the wsgi script:
    5666
    5767{{{#!python
    … …  
    6272Change it according to the path you installed the Trac libs at.
    6373
    64 === Recommended `trac.wsgi` script
    65 
    66 A somewhat robust and generic version of this file can be created using the `trac-admin <env> deploy <dir>` command which automatically substitutes the required paths (see TracInstall#cgi-bin).
    67 
    68 
    6974== Mapping requests to the script
    7075
    71 After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example).
    72 
    73 {{{
     76After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
     77
     78{{{#!apache
    7479WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
    7580
    7681<Directory /usr/local/trac/mysite/apache>
    7782    WSGIApplicationGroup %{GLOBAL}
    78     Order deny,allow
    79     Allow from all
     83    # For Apache 2.2
     84    <IfModule !mod_authz_core.c>
     85        Order deny,allow
     86        Allow from all
     87    </IfModule>
     88    # For Apache 2.4
     89    <IfModule mod_authz_core.c>
     90        Require all granted
     91    </IfModule>
    8092</Directory>
    8193}}}
    … …  
    8597If you followed the directions [TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
    8698
    87 {{{
     99{{{#!apache
    88100WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
    89101
    90102<Directory /usr/share/trac/cgi-bin>
    91103    WSGIApplicationGroup %{GLOBAL}
    92     Order deny,allow
    93     Allow from all
     104    # For Apache 2.2
     105    <IfModule !mod_authz_core.c>
     106        Order deny,allow
     107        Allow from all
     108    </IfModule>
     109    # For Apache 2.4
     110    <IfModule mod_authz_core.c>
     111        Require all granted
     112    </IfModule>
    94113</Directory>
    95114}}}
    96115
    97 In order to let Apache run the script, access to the directory in which the script resides is opened up to all of Apache. Additionally, the `WSGIApplicationGroup` directive ensures that Trac is always run in the first Python interpreter created by mod_wsgi; this is necessary because the Subversion Python bindings, which are used by Trac, don't always work in other sub-interpreters and may cause requests to hang or cause Apache to crash as a result. After adding this configuration, restart Apache, and then it should work.
    98 
    99 To test the setup of Apache, mod_wsgi and Python itself (ie. without involving Trac and dependencies), this simple wsgi application can be used to make sure that requests gets served (use as only content in your `.wsgi` script):
     116In order to let Apache run the script, access to the directory in which the script resides is opened up to all of Apache. Additionally, the `WSGIApplicationGroup` directive ensures that Trac is always run in the first Python interpreter created by mod_wsgi. This is necessary because the Subversion Python bindings, which are used by Trac, don't always work in other sub-interpreters and may cause requests to hang or cause Apache to crash. After adding this configuration, restart Apache, and then it should work.
     117
     118To test the setup of Apache, mod_wsgi and Python itself (ie without involving Trac and dependencies), this simple wsgi application can be used to make sure that requests gets served (use as only content in your `.wsgi` script):
    100119
    101120{{{#!python
    … …  
    105124}}}
    106125
    107 For more information about using the mod_wsgi specific directives, see the [http://code.google.com/p/modwsgi/wiki/ mod_wsgi's wiki] and more specifically the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac IntegrationWithTrac] page.
    108 
     126For more information about using the mod_wsgi specific directives, see the [https://code.google.com/archive/p/modwsgi/wikis mod_wsgi's wiki] and more specifically the [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki IntegrationWithTrac] page.
    109127
    110128== Configuring Authentication
    111129
    112 We describe in the the following sections different methods for setting up authentication.
    113 
    114 See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
    115 
    116 === Using Basic Authentication ===
    117 
    118 The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program to create the password file:
    119 {{{
     130The following sections describe different methods for setting up authentication. See also [http://httpd.apache.org/docs/2.4/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
     131
     132=== Using Basic Authentication
     133
     134The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
     135{{{#!sh
    120136$ htpasswd -c /somewhere/trac.htpasswd admin
    121137New password: <type password>
    … …  
    124140}}}
    125141
    126 After the first user, you dont need the "-c" option anymore:
    127 {{{
     142After the first user, you don't need the "-c" option anymore:
     143{{{#!sh
    128144$ htpasswd /somewhere/trac.htpasswd john
    129145New password: <type password>
    … …  
    132148}}}
    133149
    134   ''See the man page for `htpasswd` for full documentation.''
     150See the man page for `htpasswd` for full documentation.
    135151
    136152After you've created the users, you can set their permissions using TracPermissions.
    137153
    138 Now, you'll need to enable authentication against the password file in the Apache configuration:
    139 {{{
     154Now, you need to enable authentication against the password file in the Apache configuration:
     155{{{#!apache
    140156<Location "/trac/login">
    141157  AuthType Basic
    … …  
    146162}}}
    147163
    148 If you're hosting multiple projects you can use the same password file for all of them:
    149 {{{
     164If you are hosting multiple projects, you can use the same password file for all of them:
     165{{{#!apache
    150166<LocationMatch "/trac/[^/]+/login">
    151167  AuthType Basic
    … …  
    155171</LocationMatch>
    156172}}}
    157 Note that neither a file nor a directory named 'login' needs to exist.[[BR]]
    158 See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_basic.html mod_auth_basic] documentation.
    159 
    160 === Using Digest Authentication ===
    161 
    162 For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”.
    163 
    164 You'll have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
    165 {{{
    166 # htdigest -c /somewhere/trac.htpasswd trac admin
     173
     174Note that neither a file nor a directory named 'login' needs to exist. See also the [https://httpd.apache.org/docs/2.4/mod/mod_auth_basic.html mod_auth_basic] documentation.
     175
     176=== Using Digest Authentication
     177
     178For better security, it is recommended that you either enable SSL or at least use the "digest" authentication scheme instead of "Basic".
     179
     180You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     181{{{#!sh
     182$ htdigest -c /somewhere/trac.htpasswd trac admin
    167183}}}
    168184
    169185The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
    170186
    171 {{{
     187{{{#!apache
    172188<Location "/trac/login">
    173 
    174     AuthType Digest
    175     AuthName "trac"
    176     AuthDigestDomain /trac
    177     AuthUserFile /somewhere/trac.htpasswd
    178     Require valid-user
     189  AuthType Digest
     190  AuthName "trac"
     191  AuthDigestDomain /trac
     192  AuthUserFile /somewhere/trac.htpasswd
     193  Require valid-user
    179194</Location>
    180195}}}
    … …  
    182197For multiple environments, you can use the same `LocationMatch` as described with the previous method.
    183198
    184 '''Note: `Location` cannot be used inside .htaccess files, but must instead live within the main httpd.conf file. If you are on a shared server, you therefore will not be able to provide this level of granularity. '''
     199'''Note''': `Location` cannot be used inside .htaccess files, but must instead live within the main httpd.conf file. If you are on a shared server, you therefore will not be able to provide this level of granularity.
    185200
    186201Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
    187 {{{
    188     LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
    189 }}}
    190 
    191 
    192 See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html mod_auth_digest] documentation.
     202{{{#!apache
     203  LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
     204}}}
     205
     206See also the [https://httpd.apache.org/docs/2.4/mod/mod_auth_basic.html mod_auth_digest] documentation.
    193207
    194208=== Using LDAP Authentication
    195209
    196 Configuration for [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap] authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19)
    197 
    198 1. You need to load the following modules in Apache httpd.conf
    199 {{{
    200 LoadModule ldap_module modules/mod_ldap.so
    201 LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
    202 }}}
    203 
    204 2. Your httpd.conf also needs to look something like:
    205 
    206 {{{
     210Configuration for [https://httpd.apache.org/docs/2.4/mod/mod_ldap.html mod_ldap] authentication in Apache is more involved (httpd 2.2+ and OpenLDAP: slapd 2.3.19).
     211
     2121. You need to load the following modules in Apache httpd.conf:
     213{{{#!apache
     214  LoadModule ldap_module modules/mod_ldap.so
     215  LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
     216}}}
     2171. Your httpd.conf also needs to look something like:
     218{{{#!apache
    207219<Location /trac/>
    208220  # (if you're using it, mod_python specific settings go here)
    … …  
    218230</Location>
    219231}}}
    220 
    221 
    222 3. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
    223 
    224 
    225 Use the following as your LDAP URL:
    226 {{{
    227     AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
    228 }}}
    229 
    230 You will also need to provide an account for Apache to use when checking
    231 credentials. As this password will be listed in plaintext in the
    232 config, you should be sure to use an account specifically for this task:
    233 {{{
    234     AuthLDAPBindDN ldap-auth-user@example.com
    235     AuthLDAPBindPassword "password"
    236 }}}
    237 
    238 The whole section looks like:
    239 {{{
     2321. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory. Use the following as your LDAP URL:
     233{{{#!apache
     234  AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
     235}}}
     236 You will also need to provide an account for Apache to use when checking credentials. As this password will be listed in plain text in the configuration, you need to use an account specifically for this task:
     237{{{#!apache
     238  AuthLDAPBindDN ldap-auth-user@example.com
     239  AuthLDAPBindPassword "password"
     240}}}
     241 The whole section looks like:
     242{{{#!apache
    240243<Location /trac/>
    241244  # (if you're using it, mod_python specific settings go here)
    … …  
    251254  authzldapauthoritative Off
    252255  # require valid-user
    253   require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     256  Require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
    254257</Location>
    255258}}}
    256259
    257 Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to Global Catalog Server portion of AD (Notice the port is 3268, not the normal LDAP 389). The GCS is basically a "flattened" tree which allows searching for a user without knowing to which OU they belong.
    258 
    259 Note 2: You can also require the user be a member of a certain LDAP group, instead of
    260 just having a valid login:
    261 {{{
    262     Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     260Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to the Global Catalog Server portion of AD. Note the port is 3268, not the normal LDAP 389. The GCS is basically a "flattened" tree which allows searching for a user without knowing to which OU they belong.
     261
     262Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
     263{{{#!apache
     264  Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
    263265}}}
    264266
    265267See also:
    266   - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap
    267    
    268  - [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
    269  - [http://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
     268 - [https://httpd.apache.org/docs/2.4/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap.   
     269 - [https://httpd.apache.org/docs/2.4/mod/mod_ldap.html mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
     270 - [https://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
    270271
    271272=== Using SSPI Authentication
    272273
    273 If you are using Apache on Windows, you can use mod_auth_sspi to provide
    274 single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the
    275 following to your !VirtualHost:
    276 {{{
    277     <Location /trac/login>
    278         AuthType SSPI
    279         AuthName "Trac Login"
    280         SSPIAuth On
    281         SSPIAuthoritative On
    282         SSPIDomain MyLocalDomain
    283         SSPIOfferBasic On
    284         SSPIOmitDomain Off
    285         SSPIBasicPreferred On
    286         Require valid-user
    287     </Location>
    288 }}}
    289 
    290 Using the above, usernames in Trac will be of the form `DOMAIN\username`, so
    291 you may have to re-add permissions and such. If you do not want the domain to
    292 be part of the username, set `SSPIOmitDomain On` instead.
     274If you are using Apache on Windows, you can use mod_auth_sspi to provide single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the following to your !VirtualHost:
     275{{{#!apache
     276<Location /trac/login>
     277  AuthType SSPI
     278  AuthName "Trac Login"
     279  SSPIAuth On
     280  SSPIAuthoritative On
     281  SSPIDomain MyLocalDomain
     282  SSPIOfferBasic On
     283  SSPIOmitDomain Off
     284  SSPIBasicPreferred On
     285  Require valid-user
     286</Location>
     287}}}
     288
     289Using the above, usernames in Trac will be of the form `DOMAIN\username`, so you may have to re-add permissions and such. If you do not want the domain to be part of the username, set `SSPIOmitDomain On` instead.
    293290
    294291Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
    … …  
    296293See also [trac:TracOnWindows/Advanced].
    297294
    298 === Using Apache authentication with the Account Manager plugin's Login form ===
    299 
    300 To begin with, see the basic instructions for using the Account Manager plugin's [http://trac-hacks.org/wiki/AccountManagerPlugin/Modules#LoginModule Login module] and its [http://trac-hacks.org/wiki/AccountManagerPlugin/AuthStores#HttpAuthStore HttpAuthStore authentication module].
    301 
    302 '''Note:''' If is difficult to get !HttpAuthStore to work with WSGI when using any Account Manager version prior to acct_mgr-0.4. Upgrading is recommended.
    303 
    304 Here is an example (from the !HttpAuthStore link) using acct_mgr-0.4 for hosting a single project:
    305 {{{
    306 [components]
    307 ; be sure to enable the component
    308 acct_mgr.http.HttpAuthStore = enabled
    309 
    310 [account-manager]
    311 ; configure the plugin to use a page that is secured with http authentication
    312 authentication_url = /authFile
    313 password_store = HttpAuthStore
    314 }}}
    315 This will generally be matched with an Apache config like:
    316 {{{
    317 <Location /authFile>
    318    …HTTP authentication configuration…
    319    Require valid-user
    320 </Location>
    321 }}}
    322 Note that '''authFile''' need not exist (unless you are using Account Manager older than 0.4). See the !HttpAuthStore link above for examples where multiple Trac projects are hosted on a server.
     295=== Using CA !SiteMinder Authentication
     296
     297Setup CA !SiteMinder to protect your Trac login URL, for example `/trac/login`. Also, make sure the policy is set to include the HTTP_REMOTE_USER variable. If your site allows it, you can set this in `LocalConfig.conf`:
     298{{{#!apache
     299RemoteUserVar="WHATEVER_IT_SHOULD_BE"
     300SetRemoteUser="YES"
     301}}}
     302
     303The specific variable is site-dependent. Ask your site administrator. If your site does not allow the use of `LocalConfig.conf` for security reasons, have your site administrator set the policy on the server to set REMOTE_USER.
     304
     305Also add a !LogOffUri parameter to the agent configuration, for example `/trac/logout`.
     306
     307Then modify the trac.wsgi script generated using `trac-admin <env> deploy <dir>` to add the following lines, which extract the `HTTP_REMOTE_USER` variable and set it to `REMOTE_USER`:
     308
     309{{{#!python
     310def application(environ, start_request):
     311    # Set authenticated username on CA SiteMinder to REMOTE_USER variable
     312    # strip() is used to remove any spaces on the end of the string
     313    if 'HTTP_SM_USER' in environ:
     314        environ['REMOTE_USER'] = environ['HTTP_REMOTE_USER'].strip()
     315    ...
     316}}}
     317
     318You do not need any Apache "Location" directives.
    323319
    324320=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
    325321
    326 Per the mod_wsgi documentation linked to above, here is an example Apache configuration that a) serves the Trac instance from a virtualhost subdomain and b) uses Apache basic authentication for Trac authentication.
    327 
    328 
    329 If you want your Trac to be served from e.g. !http://trac.my-proj.my-site.org, then from the folder e.g. `/home/trac-for-my-proj`, if you used the command `trac-admin the-env initenv` to create a folder `the-env`, and you used `trac-admin the-env deploy the-deploy` to create a folder `the-deploy`, then first:
     322Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     323 - serves the Trac instance from a virtualhost subdomain
     324 - uses Apache basic authentication for Trac authentication.
     325
     326If you want your Trac to be served from eg !http://trac.my-proj.my-site.org, then from the folder eg `/home/trac-for-my-proj`, if you used the command `trac-admin the-env initenv` to create a folder `the-env`, and you used `trac-admin the-env deploy the-deploy` to create a folder `the-deploy`, then first:
    330327
    331328Create the htpasswd file:
    332 {{{
     329{{{#!sh
    333330cd /home/trac-for-my-proj/the-env
    334331htpasswd -c htpasswd firstuser
    … …  
    336333htpasswd htpasswd seconduser
    337334}}}
    338 (keep the file above your document root for security reasons)
    339 
    340 Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following contents:
    341 
    342 {{{
     335
     336Keep the file above your document root for security reasons.
     337
     338Create this file for example `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` on Ubuntu with the following content:
     339
     340{{{#!apache
    343341<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
    344342  WSGIApplicationGroup %{GLOBAL}
    … …  
    361359}}}
    362360
    363 Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
    364 
     361For subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
    365362
    366363== Troubleshooting
    … …  
    368365=== Use a recent version
    369366
    370 Please use either version 1.6, 2.4 or later of `mod_wsgi`. Versions prior to 2.4 in the 2.X branch have problems with some Apache configurations that use WSGI file wrapper extension. This extension is used in Trac to serve up attachments and static media files such as style sheets. If you are affected by this problem attachments will appear to be empty and formatting of HTML pages will appear not to work due to style sheet files not loading properly. Another frequent symptom is that binary attachment downloads are truncated. See mod_wsgi tickets [http://code.google.com/p/modwsgi/issues/detail?id=100 #100] and [http://code.google.com/p/modwsgi/issues/detail?id=132 #132].
    371 
    372 ''Note: using mod_wsgi 2.5 and Python 2.6.1 gave an Internal Server Error on my system (Apache 2.2.11 and Trac 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [http://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks''
    373 
    374 If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you'll even need version 0.3.4 or greater (see [trac:#10675] for details).
    375 
    376 === Getting Trac to work nicely with SSPI and 'Require Group' ===
    377 If like me you've set Trac up on Apache, Win32 and configured SSPI, but added a 'Require group' option to your apache configuration, then the SSPIOmitDomain option is probably not working.  If its not working your usernames in trac are probably looking like 'DOMAIN\user' rather than 'user'.
    378 
    379 This WSGI script 'fixes' things, hope it helps:
     367Please use either version 1.6, 2.4 or later of `mod_wsgi`. Versions prior to 2.4 in the 2.X branch have problems with some Apache configurations that use WSGI file wrapper extension. This extension is used in Trac to serve up attachments and static media files such as style sheets. If you are affected by this problem, attachments will appear to be empty and formatting of HTML pages will appear not to work due to style sheet files not loading properly. Another frequent symptom is that binary attachment downloads are truncated. See mod_wsgi tickets [https://code.google.com/archive/p/modwsgi/issues/100 #100] and [https://code.google.com/archive/p/modwsgi/issues/132 #132].
     368
     369'''Note''': using mod_wsgi 2.5 and Python 2.6.1 gave an Internal Server Error on my system (Apache 2.2.11 and Trac 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [http://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks
     370
     371If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you will need version 3.4 or greater. See [trac:#10675] for details.
     372
     373=== Getting Trac to work nicely with SSPI and 'Require Group'
     374
     375If you have set Trac up on Apache, Win32 and configured SSPI, but added a 'Require group' option to your Apache configuration, then the SSPIOmitDomain option is probably not working. If it is not working, your usernames in Trac probably look like 'DOMAIN\user' rather than 'user'.
     376
     377This WSGI script fixes that:
    380378{{{#!python
    381379import os
    … …  
    391389}}}
    392390
    393 
    394 === Trac with PostgreSQL ===
    395 
    396 When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as a database back-end, the server ''may'' create a lot of open database connections and thus PostgreSQL processes.
    397 
    398 A somewhat brutal workaround is to disabled connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class.
    399 
    400 But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work:
     391=== Trac with PostgreSQL
     392
     393When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as the database, the server ''may'' create a lot of open database connections and thus PostgreSQL processes.
     394
     395A somewhat brutal workaround is to disable connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class.
     396
     397But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
    401398
    402399{{{#!python
    … …  
    412409}}}
    413410
    414 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal.
    415 
    416 //This is not a recommended approach though. See also the notes at the bottom of the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac mod_wsgi's IntegrationWithTrac] wiki page.//
     411Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
     412
     413//This is not a recommended approach though. See also the notes at the bottom of the [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki mod_wsgi's IntegrationWithTrac] wiki page.//
     414
     415=== Missing Headers and Footers
     416
     417If python optimizations are enabled, then headers and footers will not be rendered. An error will be raised in Trac 1.0.11 and later when optimizations are enabled.
     418
     419In your WSGI configuration file, the `WSGIPythonOptimize` setting must be set to `0` (`1` or `2` will not work):
     420
     421{{{#!apache
     422    WSGIPythonOptimize 0
     423}}}
     424
     425On Ubuntu, the WSGI mod configuration is at `/etc/apache2/mods-enabled/wsgi.conf`.
     426
     427The same issue is seen with `PythonOptimize On` in [TracModPython#Pagelayoutissues ModPython].
    417428
    418429=== Other resources
    419430
    420 For more troubleshooting tips, see also the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [http://code.google.com/p/modwsgi/wiki/ApplicationIssues application issues] when using mod_wsgi. The wsgi page also has a [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac Integration With Trac] document.
    421 
     431For more troubleshooting tips, see also the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [https://code.google.com/archive/p/modwsgi/wikis/ApplicationIssues.wiki application issues] when using mod_wsgi. The wsgi page also has a [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki Integration With Trac] document.
    422432
    423433----
    424 See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
     434See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]