Allow using remote cache for image downloading. Also, DRY in book2* scripts

[librarian.git] / librarian / book2anything.py

diff --git a/librarian/book2anything.py b/librarian/book2anything.py
new file mode 100755 (executable)
index 0000000..7660ec7
--- /dev/null
+++ b/librarian/book2anything.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
+# Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
+#
+from collections import namedtuple
+import os.path
+import optparse
+
+from librarian import DirDocProvider, ParseError
+from librarian.parser import WLDocument
+from librarian.cover import WLCover
+
+
+class Option(object):
+    """Option for optparse. Use it like `optparse.OptionParser.add_option`."""
+    def __init__(self, *names, **options):
+        self.names = names
+        self.options = options
+
+    def add(self, parser):
+        parser.add_option(*self.names, **self.options)
+
+    def name(self):
+        return self.options['dest']
+
+    def value(self, options):
+        return getattr(options, self.name())
+
+
+class Book2Anything(object):
+    """A class for creating book2... scripts.
+    
+    Subclass it for any format you want to convert to.
+    """
+    format_name = None # Set format name, like "PDF".
+    ext = None # Set file extension, like "pdf".
+    uses_cover = False # Can it add a cover?
+    cover_optional = True # Only relevant if uses_cover
+    uses_provider = False # Does it need a DocProvider?
+    transform = None # Transform method. Uses WLDocument.as_{ext} by default.
+    parser_options = [] # List of Option objects for additional parser args.
+    transform_options = [] # List of Option objects for additional transform args.
+    transform_flags = [] # List of Option objects for supported transform flags.
+
+
+    @classmethod
+    def run(cls):
+        # Parse commandline arguments
+        usage = """Usage: %%prog [options] SOURCE [SOURCE...]
+        Convert SOURCE files to %s format.""" % cls.format_name
+
+        parser = optparse.OptionParser(usage=usage)
+
+        parser.add_option('-v', '--verbose', 
+                action='store_true', dest='verbose', default=False,
+                help='print status messages to stdout')
+        parser.add_option('-d', '--make-dir',
+                action='store_true', dest='make_dir', default=False,
+                help='create a directory for author and put the output file in it')
+        parser.add_option('-o', '--output-file',
+                dest='output_file', metavar='FILE',
+                help='specifies the output file')
+        parser.add_option('-O', '--output-dir',
+                dest='output_dir', metavar='DIR',
+                help='specifies the directory for output')
+        if cls.uses_cover:
+            if cls.cover_optional:
+                parser.add_option('-c', '--with-cover', 
+                        action='store_true', dest='with_cover', default=False,
+                        help='create default cover')
+            parser.add_option('-C', '--image-cache',
+                    dest='image_cache', metavar='URL',
+                    help='prefix for image download cache' +
+                        (' (implies --with-cover)' if cls.cover_optional else ''))
+        for option in cls.parser_options + cls.transform_options + cls.transform_flags:
+            option.add(parser)
+
+        options, input_filenames = parser.parse_args()
+
+        if len(input_filenames) < 1:
+            parser.print_help()
+            return(1)
+
+        # Prepare additional args for parser.
+        parser_args = {}
+        for option in cls.parser_options:
+            parser_args[option.name()] = option.value(options)
+        # Prepare additional args for transform method.
+        transform_args = {}
+        for option in cls.transform_options:
+            transform_args[option.name()] = option.value(options)
+        # Add flags to transform_args, if any.
+        transform_flags = [flag.name() for flag in cls.transform_flags
+                    if flag.value(options)]
+        if transform_flags:
+            transform_args['flags'] = transform_flags
+        # Add cover support, if any.
+        if cls.uses_cover:
+            if options.image_cache:
+                transform_args['cover'] = lambda x: WLCover(x, image_cache = options.image_cache)
+            elif not cls.cover_optional or options.with_cover:
+                transform_args['cover'] = WLCover
+
+
+        # Do some real work
+        try:
+            for main_input in input_filenames:
+                if options.verbose:
+                    print main_input
+
+            # Where to find input?
+            if cls.uses_provider:
+                path, fname = os.path.realpath(main_input).rsplit('/', 1)
+                provider = DirDocProvider(path)
+            else:
+                provider = None
+
+            # Where to write output?
+            if not (options.output_file or options.output_dir):
+                output_file = os.path.splitext(main_input)[0] + '.' + cls.ext
+            else:
+                output_file = None
+
+            # Do the transformation.
+            doc = WLDocument.from_file(main_input, provider=provider, **parser_args)
+            transform = cls.transform
+            if transform is None:
+                transform = getattr(WLDocument, 'as_%s' % cls.ext)
+            output = transform(doc, **transform_args)
+
+            doc.save_output_file(output,
+                output_file, options.output_dir, options.make_dir, cls.ext)
+
+        except ParseError, e:
+            print '%(file)s:%(name)s:%(message)s' % {
+                'file': main_input,
+                'name': e.__class__.__name__,
+                'message': e
+            }