Configuring Ophelia involves a number of settings variables. They can be passed as a dictionary to the Ophelia WSGI application, ophelia.wsgi.Application, upon instantiation. The package also comes with a console script that runs a wsgiref-based server and reads the same settings variables from an ini-style configuration file, as well as a paste application factory that lets Ophelia be plugged into any WSGI server that can handle a paste “ini” file.
Regardless of how the WSGI application is being served, all settings may also be overridden by accordingly named variables set in the WSGI environment of each individual request.
The settings variables will end up in the environment namespace stored on the request object. It is possible to set any number of other variables that are not recognized by Ophelia using the same configuration mechanism. This allows configuring Python modules and scripts that belong to your site’s content.
The rest of this section contains a description of all variables as well as an example of a configuration file for the wsgiref server.
Two variables must always be present:
|template_root:||The file system path to the template root directory.|
|site:||The absolute URI of the Ophelia site’s root, i.e. that part of a page’s URI that is the same for all pages served from the template directory.|
In addition, the variables described below may be specified in order to influence the request handler’s behaviour. All of them have sensible default values.
For boolean variables such as redirect_index, the values “on”, “true”, or “yes” (case-insensitive) are taken to mean True, anything else means False.
|debug:||Whether to include debug information such as formatted tracebacks in error responses. This option is turned off by default.|
Generally, a site includes documents that are not assembled from templates. They reside within a directory tree of their own whose root needs to be configured if needed. Also, if Ophelia sits behind a reverse proxy, documents from disk may be delivered more efficiently by using something like the X-Sendfile mechanism:
|document_root:||Optional, the file system path to the on-disk documents root directory.|
|xsendfile:||One of “standard”, “nginx” or “serve”. Defaults to “serve” which means on-disk documents are delivered directly by the Ophelia application. The “standard” value causes an X-Sendfile header to be sent (such as, e.g., Apache understands) while the “nginx” value causes an X-Accel-Redirect header for consumption by an nginx reverse proxy to be sent instead. In the latter case, the nginx server needs to have the /-internal-/ location configured as an “internal” alias of the document root directory.|
If a requested URL points to a directory, Ophelia will try to find a template with a special file name and build the “index” page from that. There are two configuration options concerned with the index template:
|index_name:||The name of the index template Ophelia looks for. It defaults to “index.html”.|
|redirect_index:||Whether to canonicalize the URL and redirect the browser if the path portion of the URL ends with the default index page’s name. This option is turned off by default.|
By default, Ophelia expects Python scripts and TAL templates it reads from input files to be in 7-bit ASCII encoding. There are several ways to override this default.
You can declare a character encoding both for the Python script and the template, and the two encodings may differ. To specify the Python encoding, just start the script with a Python style encoding declaration like this:
# -*- coding: utf-8 -*-
The template’s encoding is determined by looking at the “<?xml?>” tag:
<?xml coding="utf-8" ?>
specifies UTF-8 encoding for the template. The tag itself will be stripped from the template and will not appear in the rendered page.
You may also specify a default encoding for any scripts and templates to be read later during traversal. In a Python script, just do something like
__request__.splitter.script_encoding = "utf-8" __request__.splitter.template_encoding = "utf-8"
A site-wide default can be set through options:
|Encoding of Python scripts found in input files, defaults to “ascii”.|
|Encoding of TAL templates found in input files, defaults to “ascii”.|
Ophelia uses unicode internally, but an HTTP response consists of one-byte characters, so some encoding has to be applied in the end. This encoding is automatically declared in the page’s XML declaration as well as the response headers. By default, Ophelia encodes responses using UTF-8.
To set the response encoding to, say, latin-1 for a particular resource, do
__request__.response_encoding = "latin-1"
in a script. To affect the response encoding site-wide, set an option:
|Encoding of the HTTP response body, default to “utf-8”.|
By default, the page body is encoded with the response encoding and prefixed with an XML declaration before being returned by Request.build(). This can be prevented by an option if the returned value is going to be processed further instead of being sent directly to the client:
|Whether to use the unprocessed result of template evaluation as the response content.|
First of all, note that the wsgiref-based server may be usable for development but certainly not for production. Therefore, its configuration mechanism is rather simplistic. Create a configuration file, say, wsgiref.cfg, containing one section named “DEFAULT” that holds all the settings:
[DEFAULT] host = 127.0.0.1 port = 8080 template_root = /var/example/templates site = http://localhost:8080/
and run the ophelia-wsgiref script on that file:
$ ophelia-wsgiref wsgiref.cfg
As the example shows, the wsgiref server needs two pieces of additional information:
|host:||The network interface to bind to.|
|port:||The TCP port to listen at on that interface.|
The simplest possible paste configuration will just run the paste HTTP server on the Ophelia WSGI application, without any middleware. Create a file, say, paste.ini:
[server:main] use = egg:paste#http host = 127.0.0.1 port = 8080 [app:main] use = egg:ophelia set template_root = /var/example/templates set document_root = /var/example/documents set site = http://localhost:8080/
and run a paste server from it:
$ paster serve paste.ini Starting server in PID 12345. serving on http://127.0.0.1:8080