Blaszard Blaszard - 3 months ago 36
Javascript Question

Can I scrape the raw data from highcharts.js?

I want to scrape the data from a page that shows a graph using

highcharts.js
, and thus I finished to parse all the pages to get to the following page. However, the last page, the one that displays the dataset, uses
highcharts.js
to show the graph, which it seems to be near impossible to access to the raw data.

I use Python 3.5 with BeautifulSoup.

Is it still possible to parse it? If so how can I scrape it?

Answer

The data is in a script tag. You can get the script tag using bs4 and a regex. You could also extract the data using a regex but I like using /js2xml to parse js functions into a xml tree:

from bs4 import BeautifulSoup
import requests
import re
import js2xml

soup = BeautifulSoup(requests.get("http://www.worldweatheronline.com/brussels-weather-averages/be.aspx").content, "html.parser")
script = soup.find("script", text=re.compile("Highcharts.Chart")).text
parsed = js2xml.parse(script)
print js2xml.pretty_print(parsed)

That gives you:

<program>
  <functioncall>
    <function>
      <identifier name="$"/>
    </function>
    <arguments>
      <funcexpr>
        <identifier/>
        <parameters/>
        <body>
          <var name="chart"/>
          <functioncall>
            <function>
              <dotaccessor>
                <object>
                  <functioncall>
                    <function>
                      <identifier name="$"/>
                    </function>
                    <arguments>
                      <identifier name="document"/>
                    </arguments>
                  </functioncall>
                </object>
                <property>
                  <identifier name="ready"/>
                </property>
              </dotaccessor>
            </function>
            <arguments>
              <funcexpr>
                <identifier/>
                <parameters/>
                <body>
                  <assign operator="=">
                    <left>
                      <identifier name="chart"/>
                    </left>
                    <right>
                      <new>
                        <dotaccessor>
                          <object>
                            <identifier name="Highcharts"/>
                          </object>
                          <property>
                            <identifier name="Chart"/>
                          </property>
                        </dotaccessor>
                        <arguments>
                          <object>
                            <property name="chart">
                              <object>
                                <property name="renderTo">
                                  <string>tempchartcontainer</string>
                                </property>
                                <property name="type">
                                  <string>spline</string>
                                </property>
                              </object>
                            </property>
                            <property name="credits">
                              <object>
                                <property name="enabled">
                                  <boolean>false</boolean>
                                </property>
                              </object>
                            </property>
                            <property name="colors">
                              <array>
                                <string>#FF8533</string>
                                <string>#4572A7</string>
                              </array>
                            </property>
                            <property name="title">
                              <object>
                                <property name="text">
                                  <string>Average Temperature (°c) Graph for Brussels</string>
                                </property>
                              </object>
                            </property>
                            <property name="xAxis">
                              <object>
                                <property name="categories">
                                  <array>
                                    <string>January</string>
                                    <string>February</string>
                                    <string>March</string>
                                    <string>April</string>
                                    <string>May</string>
                                    <string>June</string>
                                    <string>July</string>
                                    <string>August</string>
                                    <string>September</string>
                                    <string>October</string>
                                    <string>November</string>
                                    <string>December</string>
                                  </array>
                                </property>
                                <property name="labels">
                                  <object>
                                    <property name="rotation">
                                      <number value="270"/>
                                    </property>
                                    <property name="y">
                                      <number value="40"/>
                                    </property>
                                  </object>
                                </property>
                              </object>
                            </property>
                            <property name="yAxis">
                              <object>
                                <property name="title">
                                  <object>
                                    <property name="text">
                                      <string>Temperature (°c)</string>
                                    </property>
                                  </object>
                                </property>
                              </object>
                            </property>
                            <property name="tooltip">
                              <object>
                                <property name="enabled">
                                  <boolean>true</boolean>
                                </property>
                              </object>
                            </property>
                            <property name="plotOptions">
                              <object>
                                <property name="spline">
                                  <object>
                                    <property name="dataLabels">
                                      <object>
                                        <property name="enabled">
                                          <boolean>true</boolean>
                                        </property>
                                      </object>
                                    </property>
                                    <property name="enableMouseTracking">
                                      <boolean>false</boolean>
                                    </property>
                                  </object>
                                </property>
                              </object>
                            </property>
                            <property name="series">
                              <array>
                                <object>
                                  <property name="name">
                                    <string>Average High Temp (°c)</string>
                                  </property>
                                  <property name="color">
                                    <string>#FF8533</string>
                                  </property>
                                  <property name="data">
                                    <array>
                                      <number value="6"/>
                                      <number value="8"/>
                                      <number value="11"/>
                                      <number value="14"/>
                                      <number value="19"/>
                                      <number value="21"/>
                                      <number value="23"/>
                                      <number value="23"/>
                                      <number value="19"/>
                                      <number value="15"/>
                                      <number value="9"/>
                                      <number value="6"/>
                                    </array>
                                  </property>
                                </object>
                                <object>
                                  <property name="name">
                                    <string>Average Low Temp (°c)</string>
                                  </property>
                                  <property name="color">
                                    <string>#4572A7</string>
                                  </property>
                                  <property name="data">
                                    <array>
                                      <number value="2"/>
                                      <number value="2"/>
                                      <number value="4"/>
                                      <number value="6"/>
                                      <number value="10"/>
                                      <number value="12"/>
                                      <number value="14"/>
                                      <number value="14"/>
                                      <number value="11"/>
                                      <number value="8"/>
                                      <number value="5"/>
                                      <number value="2"/>
                                    </array>
                                  </property>
                                </object>
                              </array>
                            </property>
                          </object>
                        </arguments>
                      </new>
                    </right>
                  </assign>
                </body>
              </funcexpr>
            </arguments>
          </functioncall>
        </body>
      </funcexpr>
    </arguments>
  </functioncall>
</program>

So to get all the data:

In [28]: from bs4 import BeautifulSoup  
In [29]: import requests
In [30]: import re    
In [31]: import js2xml    
In [32]: from itertools import repeat    
In [33]: from pprint import pprint as pp
In [34]: soup = BeautifulSoup(requests.get("http://www.worldweatheronline.com/brussels-weather-averages/be.aspx").content, "html.parser")

In [35]: script = soup.find("script", text=re.compile("Highcharts.Chart")).text

In [36]: parsed = js2xml.parse(script)

In [37]: data = [d.xpath(".//array/number/@value") for d in parsed.xpath("//property[@name='data']")]

In [38]: categories = parsed.xpath("//property[@name='categories']//string/text()")

In [39]: output =  list(zip(repeat(categories), data))    
In [40]: pp(output)
[(['January',
   'February',
   'March',
   'April',
   'May',
   'June',
   'July',
   'August',
   'September',
   'October',
   'November',
   'December'],
  ['6', '8', '11', '14', '19', '21', '23', '23', '19', '15', '9', '6']),
 (['January',
   'February',
   'March',
   'April',
   'May',
   'June',
   'July',
   'August',
   'September',
   'October',
   'November',
   'December'],
  ['2', '2', '4', '6', '10', '12', '14', '14', '11', '8', '5', '2'])]

Like I said you could just use a regex but js2xml I find is more reliable as erroneous spaces etc.. won't break it.

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