-
Notifications
You must be signed in to change notification settings - Fork 2
/
Copy pathhtml2md.php
357 lines (253 loc) · 8.92 KB
/
html2md.php
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
<?php
if (!function_exists('html2markdown')) {
function html2markdown($html) {
$parser = new HTML2MD($html);
return $parser->get_markdown();
}
}
class HTML2MD
{
private $doc;
public function __construct($html)
{
$html = preg_replace('~>\s+<~', '><', $html); # Strip white space between tags to ensure uniform output
$this->doc = new DOMDocument();
$this->doc->loadHTML('<?xml encoding="UTF-8"><body>' . $html . '</body>', LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD | LIBXML_NOERROR ); # Hack to load utf-8 HTML (from http://bit.ly/pVDyCt )
$this->doc->encoding = 'UTF-8';
}
public function get_markdown()
{
# Use the body tag as our root element
$body = $this->doc->getElementsByTagName("body")->item(0);
# For each element inside the body, find child elements and convert
# those to markdown #text nodes, starting with the innermost element
# and working towards the outermost element ($node).
$this->convert_children($body);
# The DOMDocument represented by $doc now consists of #text nodes, each containing a
# markdown version of the original DOM node created by convert_to_markdown().
# Return the <body> contents of $doc, first stripping html and body tags, the DOCTYPE
# and XML encoding lines, then converting entities such as & back to &.
$markdown = $this->doc->saveHTML();
// Double decode. http://www.php.net/manual/en/function.htmlentities.php#99984
$markdown = html_entity_decode($markdown, ENT_QUOTES, 'UTF-8');
$markdown = html_entity_decode($markdown, ENT_QUOTES, 'UTF-8');
$markdown = preg_replace("/<!DOCTYPE [^>]+>/", "", $markdown);
$unwanted = array('<html>','</html>','<body>','</body>', '<?xml encoding="UTF-8">', '
');
$markdown = str_replace( $unwanted, '', $markdown);
$markdown = trim($markdown, "\n\r\0\x0B");
return $markdown;
}
# Convert child nodes from the outside in
private function convert_children($node) {
if (self::has_parent_code($node)) return;
if ($node->hasChildNodes()) {
for ($length = $node->childNodes->length, $i = 0; $i < $length; $i++) {
$child = $node->childNodes->item($i);
$this->convert_children($child);
}
}
$this->convert_to_markdown($node);
}
# Convert the supplied element into its markdown equivalent,
# then swap the original element in the DOM with the markdown
# version as a #text node. This converts the HTML $doc into
# markdown while retaining the nesting and order of all tags.
private function convert_to_markdown($node)
{
$tag = $node->nodeName; #the type of element, e.g. h1
$value = $node->nodeValue; #the value of that element, e.g. The Title
switch ($tag)
{
case "p":
case "pre":
$markdown = (trim($value)) ? rtrim($value) . PHP_EOL . PHP_EOL : '';
break;
case "h1":
$markdown = "# ".$value . PHP_EOL . PHP_EOL;
break;
case "h2":
$markdown = "## ".$value . PHP_EOL. PHP_EOL;
break;
case "h3":
$markdown = "### ".$value . PHP_EOL . PHP_EOL;
break;
case "h4":
$markdown = "#### ".$value . PHP_EOL . PHP_EOL;
break;
case "h5":
$markdown = "##### ".$value . PHP_EOL . PHP_EOL;
break;
case "h6":
$markdown = "###### ".$value . PHP_EOL . PHP_EOL;
break;
case "em":
case "i":
$markdown = "*".$value."*";
break;
case "strong":
case "b":
$markdown = "**".$value."**";
break;
case "hr":
$markdown = "- - - - - -".PHP_EOL.PHP_EOL;
break;
case "br":
$markdown = " " . PHP_EOL;
break;
case "blockquote":
$markdown = $this->convert_blockquote($node);
break;
case "code":
$markdown = $this->convert_code($node);
break;
case "ol":
case "ul":
$markdown = $value . PHP_EOL;
break;
case "li":
$markdown = $this->convert_list($node);
break;
case "img":
$markdown = $this->convert_image($node);
break;
case "a":
$markdown = $this->convert_anchor($node);
break;
default:
# C14N() is the XML canonicalization function (undocumented).
# It returns the full content of the node, including surrounding tags.
$markdown = html_entity_decode(html_entity_decode($node->C14N()),ENT_QUOTES, 'UTF-8');
}
#Create a DOM text node containing the markdown equivalent of the original node
$markdown_node = $this->doc->createTextNode($markdown);
#Swap the old $node e.g. <h3>Title</h3> with the new $markdown_node e.g. ###Title
$node->parentNode->replaceChild($markdown_node, $node);
}
private function convert_image($node)
{
$src = $node->getAttribute('src');
$alt = $node->getAttribute('alt');
$markdown = '';
return $markdown;
}
private function convert_anchor($node)
{
$href = $node->getAttribute('href');
$text = $node->nodeValue;
$markdown = '['.$text.']('.$href.')';
$next_node_name = $this->get_next_node_name($node);
if ($next_node_name == 'a') {
$markdown = $markdown . ' ';
}
return $markdown;
}
private function convert_list($node)
{
#If parent is an ol, use numbers, otherwise, use dashes
$list_type = $node->parentNode->nodeName;
$value = $node->nodeValue;
if ($list_type == "ul"){
$markdown = "- ".$value . PHP_EOL;
} else {
$number = $this->get_list_position($node);
$markdown = $number.". ".$value . PHP_EOL;
}
return $markdown;
}
# Don't convert code that's inside a code block
private static function has_parent_code($node) {
for ($p = $node->parentNode; $p != false; $p = $p->parentNode) {
if (is_null($p)) return false;
if ($p->nodeName == 'code') return true;
}
return false;
}
private function convert_code($node)
{
# Store the content of the code block in an array, one entry for each line
$markdown = '';
$code_content = html_entity_decode($node->C14N(), ENT_QUOTES, 'UTF-8');
$code_content = str_replace(array("<code>","</code>"), "", $code_content);
$lines = preg_split( '/\r\n|\r|\n/', $code_content );
$total = count($lines);
# If there's more than one line of code, prepend each line with four spaces and no backticks.
if ($total > 1){
# Remove the first and last line if they're empty
$first_line = trim($lines[0]);
$last_line = trim($lines[$total-1]);
$first_line = trim($first_line, "
"); //trim XML style carriage returns too
$last_line = trim($last_line, "
");
if ( empty( $first_line ) )
array_shift($lines);
if ( empty( $last_line ) )
array_pop($lines);
$count = 1;
foreach ($lines as $line) {
$line = str_replace('
', '', $line);
$markdown .= " ".$line;
// Add newlines, except final line of the code
if ($count != $total) $markdown .= PHP_EOL;
$count++;
}
$markdown .= PHP_EOL;
} else { # There's only one line of code. It's a code span, not a block. Just wrap it with backticks.
$markdown .= "`".$lines[0]."`";
}
return $markdown;
}
private function convert_blockquote($node)
{
# Contents should have already been converted to markdown by this point,
# so we just need to add ">" symbols to each line.
$markdown = '';
$quote_content = trim($node->nodeValue);
$lines = preg_split( '/\r\n|\r|\n/', $quote_content );
$lines = array_filter($lines); //strips empty lines
foreach($lines as $line){
$markdown .= "> ".$line. PHP_EOL;
}
return PHP_EOL. $markdown ;
}
#
# Helper methods
#
# Returns numbered position of an <li> inside an <ol>
private function get_list_position($node)
{
# Get all of the li nodes inside the parent
$list_nodes = $node->parentNode->childNodes;
$total_nodes = $list_nodes->length;
$position = 1;
# Loop through all li nodes and find the one we passed
for ($a = 0; $a < $total_nodes; $a++)
{
$current_node = $list_nodes->item($a);
if ($current_node->isSameNode($node))
$position = $a + 1;
}
return $position;
}
private function get_next_node_name($node)
{
$next_node_name = null;
$current_position = $this->get_position($node);
$next_node = $node->parentNode->childNodes->item($current_position);
if ($next_node)
$next_node_name = $next_node->nodeName;
return $next_node_name;
}
private function get_position($node)
{
// Get all of the nodes inside the parent
$list_nodes = $node->parentNode->childNodes;
$total_nodes = $list_nodes->length;
$position = 1;
// Loop through all nodes and find the given $node
for ($a = 0; $a < $total_nodes; $a++) {
$current_node = $list_nodes->item($a);
if ($current_node->isSameNode($node))
$position = $a + 1;
}
return $position;
}
}