90 lines
3.5 KiB
Markdown
90 lines
3.5 KiB
Markdown
How to add a new comic to Dosage
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To add a new comic, add a new class in one of the *.py files
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in the dosagelib/plugins module.
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The files in dosagelib/plugin and the classes inside those files are
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sorted alphabetically. Add your comic to the appropriate filename.
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For example if the comic name is "Super duper comic", the new class
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should be added to dosagelib/plugins/s.py.
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Here is a complete example which is explained in detail below.
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```
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class SuperDuperComic(_BasicScraper):
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description = u'A super duper comic by Mr Smith!'
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url = 'http://superdupercomic.com/'
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rurl = escape(url)
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stripUrl = url + 'comic/%s'
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firstStripUrl = stripUrl % '1'
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imageSearch = compile(tagre("img", "src", r'(%scomicimg/[^"]+)' % rurl))
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prevSearch = compile(tagre("a", "href", r'(%scomic/\d+)' % rurl, after="prev"))
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help = 'Index format: n (unpadded)'
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```
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Let's look at each line in detail.
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```class SuperDuperComic(_BasicScraper):```
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All comic plugin classes inherit from ``_BasicScraper``.
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The classname (``SuperDuperComic`` in our example) must be unique,
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regardless of upper/lower characters.
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The user finds comics with this classname, so be sure to select
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something descriptive and easy to remember.
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```description = u'A super duper comic by Mr Smith!'```
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Next, a description should be added to the class in Unicode notation
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(u'...'). It is displayed when a user requests help for one comic with
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``dosage -m superdupercomic``.
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```url = 'http://superdupercomic.com/'```
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The URL must display the latest comic picture. This is where the
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comic image search will start. See below for some special cases.
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```rurl = escape(url)```
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This defines a variable ``rurl`` which is used in the search patterns
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below. It properly escapes all regular expression special characters
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like dots or question marks.
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```stripUrl = url + 'comic/%s'```
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This defines how a comic strip URL looks like. In our example, all
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comic strip URLs look like ``http://superdupercomic.com/comics/NNN``
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where NNN is the increasing comic number.
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```firstStripUrl = stripUrl % '1'```
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This tells Dosage what the earliest comic strip URL looks like. Dosage
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stops searching for more comics when it is encounted. In our example
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comic numbering starts with ``1``, so the first comic URL is
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``http://superdupercomic.com/comics/1``
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```imageSearch = compile(tagre("img", "src", r'(%simg/[^"]+)' % rurl))```
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Each comic page URL has one or more comic strip images. The imageSearch
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pattern must match those images in the HTML content of the page URL.
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To make it easy to match HTML tags, the ``tagre()`` function is
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helpful. The first parameter is the tag name, the second the attribute
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name and the third the attribute value. So in our example the given
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pattern whould match a tag like
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``<img src="http://superdupercomic.com/img/comic1.jpg" />``` .
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```prevSearch = compile(tagre("a", "href", r'(%scomic/\d+)' % rurl, after="prev"))```
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To search for more comics, Dosage has to look for the previous comic URL.
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The ``after=`` value in ``tagre()`` matches anything between the
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attribute value and the end of the tag.
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So this pattern assumes each comic page URL has a link to the previous
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comic, for example ``http://superdupercomic.com/comic/100`` has a
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link ``<a href="http://superdupercomic.com/comic/99" class="prev">``.
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``help = 'Index format: n (unpadded)'``
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Since the user can search comics from a given start point, the help
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must describe how the comic is numbered. Running
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``dosage superdupercomic:100`` would start getting comics from number
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100 and earlier.
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