TXT Input: Add support for embedded images that use relative URLs when converting markdown or textile. Note that this will only work if you are converting using the ebook-convert command line tool as the main calibre program moves files around, so relative references will not be valid.

src/calibre/ebooks/conversion/plugins/txt_input.py

@@ -67,10 +67,40 @@ class TXTInput(InputFormatPlugin):
             help=_('Enable extensions to markdown syntax. Extensions are formatting that is not part '
                    'of the standard markdown format. The extensions enabled by default: %default.\n'
                    'To learn more about markdown extensions, see https://pythonhosted.org/Markdown/extensions/index.html\n'
-                   'This should be a comma separated list of extensions to enable:\n') +
-                             '\n'.join('* %s: %s' % (k, MD_EXTENSIONS[k]) for k in sorted(MD_EXTENSIONS))),
+                   'This should be a comma separated list of extensions to enable:\n'
+                   ) + '\n'.join('* %s: %s' % (k, MD_EXTENSIONS[k]) for k in sorted(MD_EXTENSIONS))),
     ])
 
+    def shift_file(self, base_dir, fname, data):
+        name, ext = os.path.splitext(fname)
+        c = 1
+        while os.path.exists(os.path.join(base_dir, '{}-{}{}'.format(name, c, ext))):
+            c += 1
+        ans = os.path.join(base_dir, '{}-{}{}'.format(name, c, ext))
+        with open(ans, 'wb') as f:
+            f.write(data)
+        return f.name
+
+    def fix_resources(self, html, base_dir):
+        from html5_parser import parse
+        root = parse(html)
+        changed = False
+        for img in root.xpath('//img[@src]'):
+            src = img.get('src')
+            prefix = src.split(':', 1)[0].lower()
+            if prefix not in ('file', 'http', 'https', 'ftp') and not os.path.isabs(src):
+                src = os.path.join(base_dir, src)
+                if os.access(src, os.R_OK):
+                    with open(src, 'rb') as f:
+                        data = f.read()
+                    f = self.shift_file(base_dir, os.path.basename(src), data)
+                    changed = True
+                    img.set('src', os.path.basename(f))
+        if changed:
+            from lxml import etree
+            html = etree.tostring(root, encoding='unicode')
+        return html
+
     def convert(self, stream, options, file_ext, log,
                 accelerators):
         from calibre.ebooks.conversion.preprocess import DocAnalysis, Dehyphenator
@@ -87,6 +117,7 @@ class TXTInput(InputFormatPlugin):
         txt = ''
         log.debug('Reading text from file...')
         length = 0
+        base_dir = os.getcwdu()
 
         # Extract content from zip archive.
         if file_ext == 'txtz':
@@ -98,6 +129,8 @@ class TXTInput(InputFormatPlugin):
                     with open(x, 'rb') as tf:
                         txt += tf.read() + '\n\n'
         else:
+            if getattr(stream, 'name', None):
+                base_dir = os.path.dirname(stream.name)
             txt = stream.read()
             if file_ext in {'md', 'textile', 'markdown'}:
                 options.formatting_type = {'md': 'markdown'}.get(file_ext, file_ext)
@@ -194,6 +227,8 @@ class TXTInput(InputFormatPlugin):
             txt = preserve_spaces(txt)
 
         # Process the text using the appropriate text processor.
+        self.shifted_files = []
+        try:
             html = ''
             input_mi = None
             if options.formatting_type == 'markdown':
@@ -203,9 +238,11 @@ class TXTInput(InputFormatPlugin):
                 except RuntimeError:
                     raise ValueError('This txt file has malformed markup, it cannot be'
                         ' converted by calibre. See https://daringfireball.net/projects/markdown/syntax')
+                html = self.fix_resources(html, base_dir)
             elif options.formatting_type == 'textile':
                 log.debug('Running text through textile conversion...')
                 html = convert_textile(txt)
+                html = self.fix_resources(html, base_dir)
             else:
                 log.debug('Running text through basic conversion...')
                 flow_size = getattr(options, 'flow_size', 0)
@@ -217,24 +254,15 @@ class TXTInput(InputFormatPlugin):
             for opt in html_input.options:
                 setattr(options, opt.option.name, opt.recommended_value)
             options.input_encoding = 'utf-8'
-        base = os.getcwdu()
-        if file_ext != 'txtz' and hasattr(stream, 'name'):
-            base = os.path.dirname(stream.name)
-        fname = os.path.join(base, 'index.html')
-        c = 0
-        while os.path.exists(fname):
-            c += 1
-            fname = 'index%d.html'%c
-        htmlfile = open(fname, 'wb')
-        with htmlfile:
-            htmlfile.write(html.encode('utf-8'))
+            htmlfile = self.shift_file(base_dir, 'index.html', html.encode('utf-8'))
             odi = options.debug_pipeline
             options.debug_pipeline = None
             # Generate oeb from html conversion.
-        oeb = html_input.convert(open(htmlfile.name, 'rb'), options, 'html', log,
-                {})
+            oeb = html_input.convert(open(htmlfile, 'rb'), options, 'html', log, {})
             options.debug_pipeline = odi
-        os.remove(htmlfile.name)
+        finally:
+            for x in self.shifted_files:
+                os.remove(x)
 
         # Set metadata from file.
         if input_mi is None: