Repository: getnikola/nikola

Issue:
Do a rst2html-like tool
Maybe not supporting the whole rst2html command line, BUT! If we can:

1) Make it load rst extension plugins
2) Do the basic stuff, like compiling files

Then it will be very useful. Specially if we get some/all of the sphinx compatibility to work.



Discussion:
What sort of output do you want?  Should it use Nikola templates, or be a bare HTML fragment?  Should it inline `rst.css` or not?

It depends. For a 1st draft, I would make it take a very simple template, with the option to change it.
Probably inline rst.css


Resolving patch:
diff --git a/nikola/plugins/command/rst2html/__init__.py b/nikola/plugins/command/rst2html/__init__.py
new file mode 100644
--- /dev/null
+++ b/nikola/plugins/command/rst2html/__init__.py
@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+
+# Copyright © 2015 Chris Warrick and others.
+
+# Permission is hereby granted, free of charge, to any
+# person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the
+# Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the
+# Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice
+# shall be included in all copies or substantial portions of
+# the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
+# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+from __future__ import unicode_literals, print_function
+
+import io
+import lxml.html
+from pkg_resources import resource_filename
+from mako.template import Template
+from nikola.plugin_categories import Command
+
+
+class CommandRst2Html(Command):
+    """Compile reStructuredText to HTML, using Nikola architecture."""
+
+    name = "rst2html"
+    doc_usage = "infile"
+    doc_purpose = "compile reStructuredText to HTML files"
+
+    def _execute(self, options, args):
+        """Compile reStructuredText to standalone HTML files."""
+        compiler = self.site.plugin_manager.getPluginByName('rest', 'PageCompiler').plugin_object
+        if len(args) != 1:
+            print("This command takes only one argument (input file name).")
+            return 2
+        source = args[0]
+        with io.open(source, "r", encoding="utf8") as in_file:
+            data = in_file.read()
+            output, error_level, deps = compiler.compile_html_string(data, source, True)
+
+        rstcss_path = resource_filename('nikola', 'data/themes/base/assets/css/rst.css')
+        with io.open(rstcss_path, "r", encoding="utf8") as fh:
+            rstcss = fh.read()
+
+        template_path = resource_filename('nikola', 'plugins/command/rst2html/rst2html.tmpl')
+        template = Template(filename=template_path)
+        template_output = template.render(rstcss=rstcss, output=output)
+        parser = lxml.html.HTMLParser(remove_blank_text=True)
+        doc = lxml.html.document_fromstring(template_output, parser)
+        html = b'<!DOCTYPE html>\n' + lxml.html.tostring(doc, encoding='utf8', method='html', pretty_print=True)
+        print(html)
+        if error_level < 3:
+            exit(0)
+        else:
+            exit(1)
diff --git a/nikola/plugins/compile/rest/__init__.py b/nikola/plugins/compile/rest/__init__.py
--- a/nikola/plugins/compile/rest/__init__.py
+++ b/nikola/plugins/compile/rest/__init__.py
@@ -64,9 +64,39 @@ def register_extra_dependencies(self, post):
         """Adds dependency to post object to check .dep file."""
         post.add_dependency(lambda: self._read_extra_deps(post), 'fragment')
 
-    def compile_html(self, source, dest, is_two_file=True):
-        """Compile reSt into HTML."""
+    def compile_html_string(self, data, source_path=None, is_two_file=True):
+        """Compile reSt into HTML strings."""
+        add_ln = 0
+        if not is_two_file:
+            spl = re.split('(\n\n|\r\n\r\n)', data, maxsplit=1)
+            data = spl[-1]
+            if len(spl) != 1:
+                # If errors occur, this will be added to the line
+                # number reported by docutils so the line number
+                # matches the actual line number (off by 7 with default
+                # metadata, could be more or less depending on the post
+                # author).
+                add_ln = len(spl[0].splitlines()) + 1
+
+        default_template_path = os.path.join(os.path.dirname(__file__), 'template.txt')
+        output, error_level, deps = rst2html(
+            data, settings_overrides={
+                'initial_header_level': 1,
+                'record_dependencies': True,
+                'stylesheet_path': None,
+                'link_stylesheet': True,
+                'syntax_highlight': 'short',
+                'math_output': 'mathjax',
+                'template': default_template_path,
+            }, logger=self.logger, source_path=source_path, l_add_ln=add_ln, transforms=self.site.rst_transforms)
+        if not isinstance(output, unicode_str):
+            # To prevent some weird bugs here or there.
+            # Original issue: empty files.  `output` became a bytestring.
+            output = output.decode('utf-8')
+        return output, error_level, deps
 
+    def compile_html(self, source, dest, is_two_file=True):
+        """Compile reSt into HTML files."""
         if not has_docutils:
             req_missing(['docutils'], 'build this site (compile reStructuredText)')
         makedirs(os.path.dirname(dest))
@@ -74,33 +104,7 @@ def compile_html(self, source, dest, is_two_file=True):
         with io.open(dest, "w+", encoding="utf8") as out_file:
             with io.open(source, "r", encoding="utf8") as in_file:
                 data = in_file.read()
-                add_ln = 0
-                if not is_two_file:
-                    spl = re.split('(\n\n|\r\n\r\n)', data, maxsplit=1)
-                    data = spl[-1]
-                    if len(spl) != 1:
-                        # If errors occur, this will be added to the line
-                        # number reported by docutils so the line number
-                        # matches the actual line number (off by 7 with default
-                        # metadata, could be more or less depending on the post
-                        # author).
-                        add_ln = len(spl[0].splitlines()) + 1
-
-                default_template_path = os.path.join(os.path.dirname(__file__), 'template.txt')
-                output, error_level, deps = rst2html(
-                    data, settings_overrides={
-                        'initial_header_level': 1,
-                        'record_dependencies': True,
-                        'stylesheet_path': None,
-                        'link_stylesheet': True,
-                        'syntax_highlight': 'short',
-                        'math_output': 'mathjax',
-                        'template': default_template_path,
-                    }, logger=self.logger, source_path=source, l_add_ln=add_ln, transforms=self.site.rst_transforms)
-                if not isinstance(output, unicode_str):
-                    # To prevent some weird bugs here or there.
-                    # Original issue: empty files.  `output` became a bytestring.
-                    output = output.decode('utf-8')
+                output, error_level, deps = self.compile_html_string(data, source, is_two_file)
                 out_file.write(output)
             deps_path = dest + '.dep'
             if deps.list:


Test patch: