Support for pre-fetched HTML/Markdown content.

HTML output can be too large for the process called over the command
line. HTML data exchange now happens through an intermediate temporary
file.

platypush/plugins/http/webpage/__init__.py

@@ -2,6 +2,7 @@ import datetime
 import json
 import os
 import subprocess
+import tempfile
 
 from platypush.plugins import action
 from platypush.plugins.http.request import Plugin
@@ -23,6 +24,14 @@ class HttpWebpagePlugin(Plugin):
 
     _mercury_script = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'mercury-parser.js')
 
+    def _parse(self, proc):
+        output = ''
+
+        with subprocess.Popen(proc, stdout=subprocess.PIPE, stderr=None) as parser:
+            output = parser.communicate()[0].decode()
+
+        return output
+
     @action
     def simplify(self, url, type='html', html=None, outfile=None):
         """
@@ -60,15 +69,27 @@ class HttpWebpagePlugin(Plugin):
         """
 
         self.logger.info('Parsing URL {}'.format(url))
-        parser = subprocess.Popen(['node', self._mercury_script, url, type, html], stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)
+        proc = ['node', self._mercury_script, url, type]
-        response = parser.stdout.read().decode().strip()
+        f = None
+
+        if html:
+            f = tempfile.NamedTemporaryFile('w+', delete=False)
+            f.write(html)
+            f.flush()
+            proc.append(f.name)
 
         try:
-            response = json.loads(response)
+            response = self._parse(proc)
+        finally:
+            if f:
+                os.unlink(f.name)
+
+        try:
+            response = json.loads(response.strip())
         except Exception as e:
             raise RuntimeError('Could not parse JSON: {}. Response: {}'.format(str(e), response))
 
-        self.logger.info('Got response from Mercury API: {}'.format(response))
+        self.logger.debug('Got response from Mercury API: {}'.format(response))
         title = response.get('title', '{} on {}'.format(
             'Published' if response.get('date_published') else 'Generated',
             response.get('date_published', datetime.datetime.now().isoformat())))

platypush/plugins/http/webpage/mercury-parser.js

@@ -6,22 +6,38 @@
 
 'use strict';
 
-const parser = require('@postlight/mercury-parser');
+const fs = require('fs');
+const Mercury = require('@postlight/mercury-parser');
 
 if (process.argv.length < 3) {
-    console.error('Usage: ' + process.argv[1] + ' <url to parse> [markdown|html] [Pre-fetched content]');
+    console.error('Usage: ' + process.argv[1] + ' <url to parse> [markdown|html] [Pre-fetched HTML content file]');
     process.exit(1);
 }
 
 const url = process.argv[2];
 const type = process.argv[3] || 'html';
-const content = process.argv[4];
+const contentFile = process.argv[4];
 const args = {
     contentType: type,
-    html: content,
 };
 
-parser.parse(url, args).then(result => {
+const parse = (url, args) => {
+    Mercury.parse(url, args).then(result => {
         console.log(JSON.stringify(result));
     });
+};
+
+if (contentFile) {
+    fs.readFile(contentFile, 'utf8', (err, data) => {
+        if (err) {
+            console.error(err);
+            process.exit(1);
+        }
+
+        args.html = data;
+        parse(url, args);
+    });
+} else {
+    parse(url, args);
+}