doc/reference/html/JsonPath.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html>
   3 <head>
   4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   5 <title>JsonPath: JSON-GLib Reference Manual</title>
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
   7 <link rel="home" href="index.html" title="JSON-GLib Reference Manual">
   8 <link rel="up" href="ch02.html" title="Parser">
   9 <link rel="prev" href="JsonReader.html" title="JsonReader">
  10 <link rel="next" href="ch03.html" title="Generator">
  11 <meta name="generator" content="GTK-Doc V1.25.1 (XML mode)">
  12 <link rel="stylesheet" href="style.css" type="text/css">
  13 </head>
  14 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
  15 <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="5"><tr valign="middle">
  16 <td width="100%" align="left" class="shortcuts">
  17 <a href="#" class="shortcut">Top</a><span id="nav_description">  <span class="dim">|</span>
  18                   <a href="#JsonPath.description" class="shortcut">Description</a></span><span id="nav_hierarchy">  <span class="dim">|</span>
  19                   <a href="#JsonPath.object-hierarchy" class="shortcut">Object Hierarchy</a></span>
  20 </td>
  21 <td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
  22 <td><a accesskey="u" href="ch02.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
  23 <td><a accesskey="p" href="JsonReader.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
  24 <td><a accesskey="n" href="ch03.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
  25 </tr></table>
  26 <div class="refentry">
  27 <a name="JsonPath"></a><div class="titlepage"></div>
  28 <div class="refnamediv"><table width="100%"><tr>
  29 <td valign="top">
  30 <h2><span class="refentrytitle"><a name="JsonPath.top_of_page"></a>JsonPath</span></h2>
  31 <p>JsonPath — JSONPath implementation</p>
  32 </td>
  33 <td class="gallery_image" valign="top" align="right"></td>
  34 </tr></table></div>
  35 <div class="refsect1">
  36 <a name="JsonPath.functions"></a><h2>Functions</h2>
  37 <div class="informaltable"><table class="informaltable" width="100%" border="0">
  38 <colgroup>
  39 <col width="150px" class="functions_return">
  40 <col class="functions_name">
  41 </colgroup>
  42 <tbody>
  43 <tr>
  44 <td class="function_type">
  45 <a class="link" href="JsonPath.html" title="JsonPath"><span class="returnvalue">JsonPath</span></a> *
  46 </td>
  47 <td class="function_name">
  48 <a class="link" href="JsonPath.html#json-path-new" title="json_path_new ()">json_path_new</a> <span class="c_punctuation">()</span>
  49 </td>
  50 </tr>
  51 <tr>
  52 <td class="function_type">
  53 <span class="returnvalue">gboolean</span>
  54 </td>
  55 <td class="function_name">
  56 <a class="link" href="JsonPath.html#json-path-compile" title="json_path_compile ()">json_path_compile</a> <span class="c_punctuation">()</span>
  57 </td>
  58 </tr>
  59 <tr>
  60 <td class="function_type">
  61 <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="returnvalue">JsonNode</span></a> *
  62 </td>
  63 <td class="function_name">
  64 <a class="link" href="JsonPath.html#json-path-match" title="json_path_match ()">json_path_match</a> <span class="c_punctuation">()</span>
  65 </td>
  66 </tr>
  67 <tr>
  68 <td class="function_type">
  69 <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="returnvalue">JsonNode</span></a> *
  70 </td>
  71 <td class="function_name">
  72 <a class="link" href="JsonPath.html#json-path-query" title="json_path_query ()">json_path_query</a> <span class="c_punctuation">()</span>
  73 </td>
  74 </tr>
  75 </tbody>
  76 </table></div>
  77 </div>
  78 <div class="refsect1">
  79 <a name="JsonPath.other"></a><h2>Types and Values</h2>
  80 <div class="informaltable"><table class="informaltable" width="100%" border="0">
  81 <colgroup>
  82 <col width="150px" class="name">
  83 <col class="description">
  84 </colgroup>
  85 <tbody>
  86 <tr>
  87 <td class="datatype_keyword"> </td>
  88 <td class="function_name"><a class="link" href="JsonPath.html#JsonPath-struct" title="JsonPath">JsonPath</a></td>
  89 </tr>
  90 <tr>
  91 <td class="datatype_keyword"> </td>
  92 <td class="function_name"><a class="link" href="JsonPath.html#JsonPathClass" title="JsonPathClass">JsonPathClass</a></td>
  93 </tr>
  94 <tr>
  95 <td class="define_keyword">#define</td>
  96 <td class="function_name"><a class="link" href="JsonPath.html#JSON-PATH-ERROR:CAPS" title="JSON_PATH_ERROR">JSON_PATH_ERROR</a></td>
  97 </tr>
  98 <tr>
  99 <td class="datatype_keyword">enum</td>
 100 <td class="function_name"><a class="link" href="JsonPath.html#JsonPathError" title="enum JsonPathError">JsonPathError</a></td>
 101 </tr>
 102 </tbody>
 103 </table></div>
 104 </div>
 105 <div class="refsect1">
 106 <a name="JsonPath.object-hierarchy"></a><h2>Object Hierarchy</h2>
 107 <pre class="screen">    GObject
 108     <span class="lineart">╰──</span> JsonPath
 109 </pre>
 110 </div>
 111 <div class="refsect1">
 112 <a name="JsonPath.description"></a><h2>Description</h2>
 113 <p><a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> is a simple class implementing the JSONPath syntax for extracting
 114 data out of a JSON tree. While the semantics of the JSONPath expressions are
 115 heavily borrowed by the XPath specification for XML, the syntax follows the
 116 ECMAScript origins of JSON.</p>
 117 <p>Once a <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance has been created, it has to compile a JSONPath
 118 expression using <a class="link" href="JsonPath.html#json-path-compile" title="json_path_compile ()"><code class="function">json_path_compile()</code></a> before being able to match it to a
 119 JSON tree; the same <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance can be used to match multiple JSON
 120 trees. It it also possible to compile a new JSONPath expression using the
 121 same <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance; the previous expression will be discarded only if
 122 the compilation of the new expression is successful.</p>
 123 <p>The simple convenience function <a class="link" href="JsonPath.html#json-path-query" title="json_path_query ()"><code class="function">json_path_query()</code></a> can be used for one-off
 124 matching.</p>
 125 <div class="refsect3">
 126 <a name="id-1.4.3.4.6.5"></a><h4>Syntax of the JSONPath expressions</h4>
 127 <p>A JSONPath expression is composed by path indices and operators.
 128 Each path index can either be a member name or an element index inside
 129 a JSON tree. A JSONPath expression must start with the '$' operator; each
 130 path index is separated using either the dot notation or the bracket
 131 notation, e.g.:</p>
 132 <div class="informalexample">
 133   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 134     <tbody>
 135       <tr>
 136         <td class="listing_lines" align="right"><pre>1
 137 2
 138 3
 139 4
 140 5</pre></td>
 141         <td class="listing_code"><pre class="programlisting"><span class="comment">// dot notation</span>
 142 <span class="normal">$</span><span class="symbol">.</span><span class="normal">store</span><span class="symbol">.</span><span class="normal">book</span><span class="symbol">[</span><span class="number">0</span><span class="symbol">].</span><span class="normal">title</span>
 143
 144 <span class="comment">// bracket notation</span>
 145 <span class="normal">$</span><span class="symbol">[</span><span class="string">'store'</span><span class="symbol">][</span><span class="string">'book'</span><span class="symbol">][</span><span class="number">0</span><span class="symbol">][</span><span class="string">'title'</span><span class="symbol">]</span></pre></td>
 146       </tr>
 147     </tbody>
 148   </table>
 149 </div>
 150
 151 <p></p>
 152 <p>The available operators are:</p>
 153 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 154 <li class="listitem"><p>Root node
 155 The '$' character represents the root node of the JSON tree, and
 156 matches the entire document.</p></li>
 157 <li class="listitem"><p>Child nodes can either be matched using '.' or '[]'. For instance,
 158 both <code class="literal">$.store.book</code> and `$'store' match the contents of
 159 the book member of the store object.</p></li>
 160 <li class="listitem"><p>Child nodes can be reached without specifying the whole tree structure
 161 through the recursive descent operator, or '..'. For instance,
 162 <code class="literal">$..author</code> matches all author member in every object.</p></li>
 163 <li class="listitem"><p>Child nodes can grouped through the wildcard operator, or '*'. For
 164 instance, <code class="literal">$.store.book[*].author</code> matches all author members of any
 165 object element contained in the book array of the store object.</p></li>
 166 <li class="listitem"><p>Element nodes can be accessed using their index (starting from zero)
 167 in the subscript operator '[]'. For instance, <code class="literal">$.store.book[0]</code> matches
 168 the first element of the book array of the store object.</p></li>
 169 <li class="listitem"><p>Subsets of element nodes can be accessed using the set notation
 170 operator '[start,end]'. For instance, <code class="literal">$.store.book[0,2]</code> matches the
 171 first, second, and third elements of the book array of the store
 172 object.</p></li>
 173 <li class="listitem"><p>Slices of element nodes can be accessed using the slice notation
 174 operation '[start:end:step]'. If start is omitted, the starting index
 175 of the slice is implied to be zero; if end is omitted, the ending index
 176 of the slice is implied to be the length of the array; if step is
 177 omitted, the step of the slice is implied to be 1. For instance,
 178 <code class="literal">$.store.book[:2]</code> matches the first two elements of the book array
 179 of the store object.</p></li>
 180 </ul></div>
 181 <p>More information about JSONPath is available on Stefan Gössner's
 182 <a class="ulink" href="http://goessner.net/articles/JsonPath/" target="_top">JSONPath website</a>.</p>
 183 </div>
 184 <div class="refsect3">
 185 <a name="id-1.4.3.4.6.6"></a><h4>Example of JSONPath matches</h4>
 186 <p>The following example shows some of the results of using <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a>
 187 on a JSON tree. We use the following JSON description of a bookstore:</p>
 188 <div class="informalexample">
 189   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 190     <tbody>
 191       <tr>
 192         <td class="listing_lines" align="right"><pre>1
 193 2
 194 3
 195 4
 196 5
 197 6
 198 7
 199 8
 200 9
 201 10
 202 11
 203 12
 204 13
 205 14
 206 15
 207 16</pre></td>
 208         <td class="listing_code"><pre class="programlisting"><span class="cbracket">{</span><span class="normal"> </span><span class="string">"store"</span><span class="symbol">:</span><span class="normal"> </span><span class="cbracket">{</span>
 209 <span class="normal">    </span><span class="string">"book"</span><span class="symbol">:</span><span class="normal"> </span><span class="symbol">[</span>
 210 <span class="normal">      </span><span class="cbracket">{</span><span class="normal"> </span><span class="string">"category"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"reference"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"author"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Nigel Rees"</span><span class="symbol">,</span>
 211 <span class="normal">        </span><span class="string">"title"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Sayings of the Century"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"price"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"8.95"</span><span class="normal">  </span><span class="cbracket">}</span><span class="symbol">,</span>
 212 <span class="normal">      </span><span class="cbracket">{</span><span class="normal"> </span><span class="string">"category"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"fiction"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"author"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Evelyn Waugh"</span><span class="symbol">,</span>
 213 <span class="normal">        </span><span class="string">"title"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Sword of Honour"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"price"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"12.99"</span><span class="normal"> </span><span class="cbracket">}</span><span class="symbol">,</span>
 214 <span class="normal">      </span><span class="cbracket">{</span><span class="normal"> </span><span class="string">"category"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"fiction"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"author"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Herman Melville"</span><span class="symbol">,</span>
 215 <span class="normal">        </span><span class="string">"title"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"Moby Dick"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"isbn"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"0-553-21311-3"</span><span class="symbol">,</span>
 216 <span class="normal">        </span><span class="string">"price"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"8.99"</span><span class="normal"> </span><span class="cbracket">}</span><span class="symbol">,</span>
 217 <span class="normal">      </span><span class="cbracket">{</span><span class="normal"> </span><span class="string">"category"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"fiction"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"author"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"J. R. R. Tolkien"</span><span class="symbol">,</span>
 218 <span class="normal">        </span><span class="string">"title"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"The Lord of the Rings"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"isbn"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"0-395-19395-8"</span><span class="symbol">,</span>
 219 <span class="normal">        </span><span class="string">"price"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"22.99"</span><span class="normal"> </span><span class="cbracket">}</span>
 220 <span class="normal">    </span><span class="symbol">],</span>
 221 <span class="normal">    </span><span class="string">"bicycle"</span><span class="symbol">:</span><span class="normal"> </span><span class="cbracket">{</span><span class="normal"> </span><span class="string">"color"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"red"</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"price"</span><span class="symbol">:</span><span class="normal"> </span><span class="string">"19.95"</span><span class="normal"> </span><span class="cbracket">}</span>
 222 <span class="normal">  </span><span class="cbracket">}</span>
 223 <span class="cbracket">}</span></pre></td>
 224       </tr>
 225     </tbody>
 226   </table>
 227 </div>
 228
 229 <p></p>
 230 <p>We can parse the JSON using <a class="link" href="JsonParser.html" title="JsonParser"><span class="type">JsonParser</span></a>:</p>
 231 <div class="informalexample">
 232   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 233     <tbody>
 234       <tr>
 235         <td class="listing_lines" align="right"><pre>1
 236 2</pre></td>
 237         <td class="listing_code"><pre class="programlisting"><span class="usertype">JsonParser</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">parser </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="JsonParser.html#json-parser-new">json_parser_new</a></span><span class="normal"> </span><span class="symbol">();</span>
 238 <span class="function"><a href="JsonParser.html#json-parser-load-from-data">json_parser_load_from_data</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">parser</span><span class="symbol">,</span><span class="normal"> json_data</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">-</span><span class="number">1</span><span class="symbol">,</span><span class="normal"> NULL</span><span class="symbol">);</span></pre></td>
 239       </tr>
 240     </tbody>
 241   </table>
 242 </div>
 243
 244 <p></p>
 245 <p>If we run the following code:</p>
 246 <div class="informalexample">
 247   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 248     <tbody>
 249       <tr>
 250         <td class="listing_lines" align="right"><pre>1
 251 2
 252 3
 253 4</pre></td>
 254         <td class="listing_code"><pre class="programlisting"><span class="usertype">JsonNode</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">result</span><span class="symbol">;</span>
 255 <span class="usertype">JsonPath</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">path </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="JsonPath.html#json-path-new">json_path_new</a></span><span class="normal"> </span><span class="symbol">();</span>
 256 <span class="function"><a href="JsonPath.html#json-path-compile">json_path_compile</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">path</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"$.store..author"</span><span class="symbol">,</span><span class="normal"> NULL</span><span class="symbol">);</span>
 257 <span class="normal">result </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="JsonPath.html#json-path-match">json_path_match</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">path</span><span class="symbol">,</span><span class="normal"> </span><span class="function"><a href="JsonParser.html#json-parser-get-root">json_parser_get_root</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">parser</span><span class="symbol">));</span></pre></td>
 258       </tr>
 259     </tbody>
 260   </table>
 261 </div>
 262
 263 <p></p>
 264 <p>The result <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> will contain an array with all values of the
 265 author member of the objects in the JSON tree. If we use a
 266 <a class="link" href="JsonGenerator.html" title="JsonGenerator"><span class="type">JsonGenerator</span></a> to convert the <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> to a string and print it:</p>
 267 <div class="informalexample">
 268   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 269     <tbody>
 270       <tr>
 271         <td class="listing_lines" align="right"><pre>1
 272 2
 273 3
 274 4</pre></td>
 275         <td class="listing_code"><pre class="programlisting"><span class="usertype">JsonGenerator</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">generator </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="JsonGenerator.html#json-generator-new">json_generator_new</a></span><span class="normal"> </span><span class="symbol">();</span>
 276 <span class="function"><a href="JsonGenerator.html#json-generator-set-root">json_generator_set_root</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">generator</span><span class="symbol">,</span><span class="normal"> result</span><span class="symbol">);</span>
 277 <span class="type">char</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">str </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="JsonGenerator.html#json-generator-to-data">json_generator_to_data</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">generator</span><span class="symbol">,</span><span class="normal"> NULL</span><span class="symbol">);</span>
 278 <span class="function">g_print</span><span class="normal"> </span><span class="symbol">(</span><span class="string">"Results: %s</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">,</span><span class="normal"> str</span><span class="symbol">);</span></pre></td>
 279       </tr>
 280     </tbody>
 281   </table>
 282 </div>
 283
 284 <p></p>
 285 <p>The output will be:</p>
 286 <div class="informalexample">
 287   <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 288     <tbody>
 289       <tr>
 290         <td class="listing_lines" align="right"><pre>1</pre></td>
 291         <td class="listing_code"><pre class="programlisting"><span class="symbol">[</span><span class="string">"Nigel Rees"</span><span class="symbol">,</span><span class="string">"Evelyn Waugh"</span><span class="symbol">,</span><span class="string">"Herman Melville"</span><span class="symbol">,</span><span class="string">"J. R. R. Tolkien"</span><span class="symbol">]</span></pre></td>
 292       </tr>
 293     </tbody>
 294   </table>
 295 </div>
 296
 297 <p></p>
 298 <p><a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> is available since JSON-GLib 0.14</p>
 299 </div>
 300 </div>
 301 <div class="refsect1">
 302 <a name="JsonPath.functions_details"></a><h2>Functions</h2>
 303 <div class="refsect2">
 304 <a name="json-path-new"></a><h3>json_path_new ()</h3>
 305 <pre class="programlisting"><a class="link" href="JsonPath.html" title="JsonPath"><span class="returnvalue">JsonPath</span></a> *
 306 json_path_new (<em class="parameter"><code><span class="type">void</span></code></em>);</pre>
 307 <p>Creates a new <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance.</p>
 308 <p>Once created, the <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> object should be used with <a class="link" href="JsonPath.html#json-path-compile" title="json_path_compile ()"><code class="function">json_path_compile()</code></a>
 309 and <a class="link" href="JsonPath.html#json-path-match" title="json_path_match ()"><code class="function">json_path_match()</code></a>.</p>
 310 <div class="refsect3">
 311 <a name="json-path-new.returns"></a><h4>Returns</h4>
 312 <p> the newly created <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance. Use
 313 <code class="function">g_object_unref()</code> to free the allocated resources when done. </p>
 314 <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p>
 315 </div>
 316 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 317 </div>
 318 <hr>
 319 <div class="refsect2">
 320 <a name="json-path-compile"></a><h3>json_path_compile ()</h3>
 321 <pre class="programlisting"><span class="returnvalue">gboolean</span>
 322 json_path_compile (<em class="parameter"><code><a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> *path</code></em>,
 323                    <em class="parameter"><code>const <span class="type">char</span> *expression</code></em>,
 324                    <em class="parameter"><code><span class="type">GError</span> **error</code></em>);</pre>
 325 <p>Validates and decomposes <em class="parameter"><code>expression</code></em>
 326 .</p>
 327 <p>A JSONPath expression must be compiled before calling <a class="link" href="JsonPath.html#json-path-match" title="json_path_match ()"><code class="function">json_path_match()</code></a>.</p>
 328 <div class="refsect3">
 329 <a name="json-path-compile.parameters"></a><h4>Parameters</h4>
 330 <div class="informaltable"><table class="informaltable" width="100%" border="0">
 331 <colgroup>
 332 <col width="150px" class="parameters_name">
 333 <col class="parameters_description">
 334 <col width="200px" class="parameters_annotations">
 335 </colgroup>
 336 <tbody>
 337 <tr>
 338 <td class="parameter_name"><p>path</p></td>
 339 <td class="parameter_description"><p>a <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a></p></td>
 340 <td class="parameter_annotations"> </td>
 341 </tr>
 342 <tr>
 343 <td class="parameter_name"><p>expression</p></td>
 344 <td class="parameter_description"><p>a JSONPath expression</p></td>
 345 <td class="parameter_annotations"> </td>
 346 </tr>
 347 <tr>
 348 <td class="parameter_name"><p>error</p></td>
 349 <td class="parameter_description"><p>return location for a <span class="type">GError</span>, or <code class="literal">NULL</code></p></td>
 350 <td class="parameter_annotations"> </td>
 351 </tr>
 352 </tbody>
 353 </table></div>
 354 </div>
 355 <div class="refsect3">
 356 <a name="json-path-compile.returns"></a><h4>Returns</h4>
 357 <p> <code class="literal">TRUE</code> on success; on error, <em class="parameter"><code>error</code></em>
 358 will be set with
 359 the <a class="link" href="JsonPath.html#JSON-PATH-ERROR:CAPS" title="JSON_PATH_ERROR"><code class="literal">JSON_PATH_ERROR</code></a> domain and a code from the <a class="link" href="JsonPath.html#JsonPathError" title="enum JsonPathError"><span class="type">JsonPathError</span></a>
 360 enumeration, and <code class="literal">FALSE</code> will be returned</p>
 361 </div>
 362 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 363 </div>
 364 <hr>
 365 <div class="refsect2">
 366 <a name="json-path-match"></a><h3>json_path_match ()</h3>
 367 <pre class="programlisting"><a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="returnvalue">JsonNode</span></a> *
 368 json_path_match (<em class="parameter"><code><a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> *path</code></em>,
 369                  <em class="parameter"><code><a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> *root</code></em>);</pre>
 370 <p>Matches the JSON tree pointed by <em class="parameter"><code>root</code></em>
 371  using the expression compiled
 372 into the <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a>.</p>
 373 <p>The matching <a href="json-glib-JSON-Node.html#JsonNode-struct"><span class="type">JsonNodes</span></a> will be copied into a <a class="link" href="json-glib-JSON-Array.html#JsonArray"><span class="type">JsonArray</span></a> and
 374 returned wrapped in a <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a>.</p>
 375 <div class="refsect3">
 376 <a name="json-path-match.parameters"></a><h4>Parameters</h4>
 377 <div class="informaltable"><table class="informaltable" width="100%" border="0">
 378 <colgroup>
 379 <col width="150px" class="parameters_name">
 380 <col class="parameters_description">
 381 <col width="200px" class="parameters_annotations">
 382 </colgroup>
 383 <tbody>
 384 <tr>
 385 <td class="parameter_name"><p>path</p></td>
 386 <td class="parameter_description"><p>a compiled <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a></p></td>
 387 <td class="parameter_annotations"> </td>
 388 </tr>
 389 <tr>
 390 <td class="parameter_name"><p>root</p></td>
 391 <td class="parameter_description"><p>a <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a></p></td>
 392 <td class="parameter_annotations"> </td>
 393 </tr>
 394 </tbody>
 395 </table></div>
 396 </div>
 397 <div class="refsect3">
 398 <a name="json-path-match.returns"></a><h4>Returns</h4>
 399 <p> a newly-created <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> of type
 400 <a class="link" href="json-glib-JSON-Node.html#JSON-NODE-ARRAY:CAPS"><code class="literal">JSON_NODE_ARRAY</code></a> containing an array of matching <a href="json-glib-JSON-Node.html#JsonNode-struct"><span class="type">JsonNodes</span></a>.
 401 Use <a class="link" href="json-glib-JSON-Node.html#json-node-unref" title="json_node_unref ()"><code class="function">json_node_unref()</code></a> when done. </p>
 402 <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p>
 403 </div>
 404 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 405 </div>
 406 <hr>
 407 <div class="refsect2">
 408 <a name="json-path-query"></a><h3>json_path_query ()</h3>
 409 <pre class="programlisting"><a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="returnvalue">JsonNode</span></a> *
 410 json_path_query (<em class="parameter"><code>const <span class="type">char</span> *expression</code></em>,
 411                  <em class="parameter"><code><a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> *root</code></em>,
 412                  <em class="parameter"><code><span class="type">GError</span> **error</code></em>);</pre>
 413 <p>Queries a JSON tree using a JSONPath expression.</p>
 414 <p>This function is a simple wrapper around <a class="link" href="JsonPath.html#json-path-new" title="json_path_new ()"><code class="function">json_path_new()</code></a>,
 415 <a class="link" href="JsonPath.html#json-path-compile" title="json_path_compile ()"><code class="function">json_path_compile()</code></a> and <a class="link" href="JsonPath.html#json-path-match" title="json_path_match ()"><code class="function">json_path_match()</code></a>. It implicitly
 416 creates a <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> instance, compiles <em class="parameter"><code>expression</code></em>
 417  and
 418 matches it against the JSON tree pointed by <em class="parameter"><code>root</code></em>
 419 .</p>
 420 <div class="refsect3">
 421 <a name="json-path-query.parameters"></a><h4>Parameters</h4>
 422 <div class="informaltable"><table class="informaltable" width="100%" border="0">
 423 <colgroup>
 424 <col width="150px" class="parameters_name">
 425 <col class="parameters_description">
 426 <col width="200px" class="parameters_annotations">
 427 </colgroup>
 428 <tbody>
 429 <tr>
 430 <td class="parameter_name"><p>expression</p></td>
 431 <td class="parameter_description"><p>a JSONPath expression</p></td>
 432 <td class="parameter_annotations"> </td>
 433 </tr>
 434 <tr>
 435 <td class="parameter_name"><p>root</p></td>
 436 <td class="parameter_description"><p>the root of a JSON tree</p></td>
 437 <td class="parameter_annotations"> </td>
 438 </tr>
 439 <tr>
 440 <td class="parameter_name"><p>error</p></td>
 441 <td class="parameter_description"><p>return location for a <span class="type">GError</span>, or <code class="literal">NULL</code></p></td>
 442 <td class="parameter_annotations"> </td>
 443 </tr>
 444 </tbody>
 445 </table></div>
 446 </div>
 447 <div class="refsect3">
 448 <a name="json-path-query.returns"></a><h4>Returns</h4>
 449 <p> a newly-created <a class="link" href="json-glib-JSON-Node.html#JsonNode"><span class="type">JsonNode</span></a> of type
 450 <a class="link" href="json-glib-JSON-Node.html#JSON-NODE-ARRAY:CAPS"><code class="literal">JSON_NODE_ARRAY</code></a> containing an array of matching <a href="json-glib-JSON-Node.html#JsonNode-struct"><span class="type">JsonNodes</span></a>.
 451 Use <a class="link" href="json-glib-JSON-Node.html#json-node-unref" title="json_node_unref ()"><code class="function">json_node_unref()</code></a> when done. </p>
 452 <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p>
 453 </div>
 454 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 455 </div>
 456 </div>
 457 <div class="refsect1">
 458 <a name="JsonPath.other_details"></a><h2>Types and Values</h2>
 459 <div class="refsect2">
 460 <a name="JsonPath-struct"></a><h3>JsonPath</h3>
 461 <pre class="programlisting">typedef struct _JsonPath JsonPath;</pre>
 462 <p>The <code class="literal">JsonPath</code> structure is an opaque object whose members cannot be
 463 directly accessed except through the provided API.</p>
 464 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 465 </div>
 466 <hr>
 467 <div class="refsect2">
 468 <a name="JsonPathClass"></a><h3>JsonPathClass</h3>
 469 <pre class="programlisting">typedef struct _JsonPathClass JsonPathClass;</pre>
 470 <p>The <code class="literal">JsonPathClass</code> structure is an opaque object class whose members
 471 cannot be directly accessed.</p>
 472 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 473 </div>
 474 <hr>
 475 <div class="refsect2">
 476 <a name="JSON-PATH-ERROR:CAPS"></a><h3>JSON_PATH_ERROR</h3>
 477 <pre class="programlisting">#define JSON_PATH_ERROR         (json_path_error_quark ())
 478 </pre>
 479 <p>Error domain for <a class="link" href="JsonPath.html" title="JsonPath"><span class="type">JsonPath</span></a> errors</p>
 480 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 481 </div>
 482 <hr>
 483 <div class="refsect2">
 484 <a name="JsonPathError"></a><h3>enum JsonPathError</h3>
 485 <p>Error code enumeration for the <a class="link" href="JsonPath.html#JSON-PATH-ERROR:CAPS" title="JSON_PATH_ERROR"><code class="literal">JSON_PATH_ERROR</code></a> domain.</p>
 486 <div class="refsect3">
 487 <a name="JsonPathError.members"></a><h4>Members</h4>
 488 <div class="informaltable"><table class="informaltable" width="100%" border="0">
 489 <colgroup>
 490 <col width="300px" class="enum_members_name">
 491 <col class="enum_members_description">
 492 <col width="200px" class="enum_members_annotations">
 493 </colgroup>
 494 <tbody><tr>
 495 <td class="enum_member_name"><p><a name="JSON-PATH-ERROR-INVALID-QUERY:CAPS"></a>JSON_PATH_ERROR_INVALID_QUERY</p></td>
 496 <td class="enum_member_description">
 497 <p>Invalid query</p>
 498 </td>
 499 <td class="enum_member_annotations"> </td>
 500 </tr></tbody>
 501 </table></div>
 502 </div>
 503 <p class="since">Since: <a class="link" href="ix08.html#api-index-0.14">0.14</a></p>
 504 </div>
 505 </div>
 506 </div>
 507 <div class="footer">
 508 <hr>Generated by GTK-Doc V1.25.1</div>
 509 </body>
 510 </html>