利用wikipedia 的API实现对其内容的查询

wikipedia提供了api可以供我们对其内容进行操作。其API文档地址为：

http://en.wikipedia.org/w/api.php

列举一些常见用法：

1、全文搜索

http://en.wikipedia.org/w/api.php?action=query&list=search&srsearch=fluoxetine

srsearch为要检索的内容

结果：

1. <?xml version="1.0"?>
2. <api>
3. <query>
4. <searchinfo totalhits="224" />
5. <search>
6. <p ns="0" title="Fluoxetine" snippet="&lt;span class='searchmatch'&gt;Fluoxetine&lt;/span&gt; (also known by the tradenames Prozac, Sarafem) is an antidepressant  of the selective serotonin reuptake inhibitor  (SSRI) class &lt;b&gt;...&lt;/b&gt; " size="53978" wordcount="7052" timestamp="2010-10-31T23:22:00Z" />
7. <p ns="0" title="Olanzapine/fluoxetine" snippet="The drug  combination olanzapine/&lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt; (trade name Symbyax, created by Eli Lilly and Company ) is a single capsule containing the  &lt;b&gt;...&lt;/b&gt; " size="5703" wordcount="629" timestamp="2010-09-21T09:10:34Z" />
8. <p ns="0" title="Sertraline" snippet="Evidence suggests that sertraline may work better than &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;  (Prozac) for some subtypes of depression.  Sertraline is highly  &lt;b&gt;...&lt;/b&gt; " size="104510" wordcount="13933" timestamp="2010-10-28T22:13:04Z" />
9. <p ns="0" title="Antidepressant" snippet="The first such compound to be patented was zimelidine  in 1971, while the first released clinically was indalpine . &lt;span class='searchmatch'&gt;Fluoxetine&lt;/span&gt;  was  &lt;b&gt;...&lt;/b&gt; " size="128712" wordcount="17532" timestamp="2010-10-30T08:05:06Z" />
10. <p ns="0" title="Selective serotonin reuptake inhibitor" snippet="four newer antidepressants (including the SSRIs paroxetine  and &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt; , and two non-SSRI antidepressants nefazodone  and venlafaxine ).  &lt;b&gt;...&lt;/b&gt; " size="78327" wordcount="10398" timestamp="2010-11-01T00:11:30Z" />
11. <p ns="0" title="Paroxetine" snippet="Unlike two other popular SSRI antidepressants, &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;  and sertraline , paroxetine is associated with clinically significant weight  &lt;b&gt;...&lt;/b&gt; " size="48886" wordcount="6491" timestamp="2010-10-31T23:11:12Z" />
12. <p ns="0" title="Venlafaxine" snippet="Its efficacy is similar to or better than sertraline  (Zoloft) and &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;  (Prozac), depending on the criteria and rating scales used &lt;b&gt;...&lt;/b&gt; " size="49655" wordcount="6574" timestamp="2010-11-01T00:38:00Z" />
13. <p ns="0" title="Olanzapine" snippet="Olanzapine (trade names Zyprexa, Zalasta, Zolafren, Olzapin, Oferta, Zypadhera or in combination with &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;  Symbyax ) is an atypical  &lt;b&gt;...&lt;/b&gt; " size="34028" wordcount="4540" timestamp="2010-10-30T17:45:42Z" />
14. <p ns="0" title="Prozac (disambiguation)" snippet="Prozac  is a proprietary name for the antidepressant drug &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;. Prozac may also refer to:  Prozac+ , an Italian punk band &lt;b&gt;...&lt;/b&gt; " size="581" wordcount="78" timestamp="2010-04-23T20:24:31Z" />
15. <p ns="0" title="SSRI discontinuation syndrome" snippet="paroxetine  having the highest number of withdrawal syndrome reports and &lt;span class='searchmatch'&gt;fluoxetine&lt;/span&gt;  the highest number of drug dependence reports; the note &lt;b&gt;...&lt;/b&gt; " size="41099" wordcount="5444" timestamp="2010-09-23T06:19:55Z" />
16. </search>
17. </query>
18. <query-continue>
19. <search sroffset="10" />
20. </query-continue>
21. </api>

2、列举wikipedia 的 category：

http://en.wikipedia.org/w/api.php?action=query&list=allcategories&acprefix=drug&aclimit=10

返回10条以drug开头的category；

结果：

1. <?xml version="1.0"?>
2. <api>
3. <query>
4. <allcategories>
5. <c xml:space="preserve">Drug-induced Suicide</c>
6. <c xml:space="preserve">Drug-realted suicides</c>
7. <c xml:space="preserve">Drug-related Films</c>
8. <c xml:space="preserve">Drug-related Suicides</c>
9. <c xml:space="preserve">Drug-related death in California</c>
10. <c xml:space="preserve">Drug-related deaths</c>
11. <c xml:space="preserve">Drug-related deaths by country</c>
12. <c xml:space="preserve">Drug-related deaths in Alabama</c>
13. <c xml:space="preserve">Drug-related deaths in Alaska</c>
14. <c xml:space="preserve">Drug-related deaths in Arizona</c>
15. </allcategories>
16. </query>
17. <query-continue>
18. <allcategories acfrom="Drug-related deaths in Arkansas" />
19. </query-continue>
20. </api>

3、返回具有相应title页面的timestamp|user|comment|content 信息；

http://en.wikipedia.org/w/api.php?action=query&prop=revisions&titles=api&rvprop=timestamp|user|comment|content

结果：

1. <?xml version="1.0"?>
2. <api>
3. <query>
4. <pages>
5. <page pageid="27697087" ns="0" title="API">
6. <revisions>
7. <rev user="Graham87" timestamp="2010-06-13T08:41:17Z" comment="Protected API: restore protection ([edit=sysop] (indefinite) [move=sysop] (indefinite))" xml:space="preserve">#REDIRECT [[Application programming interface]]{{R from abbreviation}}</rev>
8. </revisions>
9. </page>
10. </pages>
11. </query>
12. </api>

4、解析页面：

http://en.wikipedia.org/w/api.php?action=parse&format=xml&page=fluoxetine

用上面的查询返回的[content]是wikipedia的标记格式，这个api返回的是html格式的文本：

可以用xpath="api/parse/text" 返回html内容。

* action=parse *
  This module parses wikitext and returns parser output

This module requires read rights.
Parameters:
  title          - Title of page the text belongs to
                   Default: API
  text           - Wikitext to parse
  summary        - Summary to parse
  page           - Parse the content of this page. Cannot be used together with text and title
  redirects      - If the page parameter is set to a redirect, resolve it
  oldid          - Parse the content of this revision. Overrides page
  prop           - Which pieces of information to get.
                   NOTE: Section tree is only generated if there are more than 4 sections, or if the __TOC__ keyword is present
                   Values (separate with '|'): text, langlinks, categories, links, templates, images, externallinks, sections, revid, displaytitle, headitems, headhtml
                   Default: text|langlinks|categories|links|templates|images|externallinks|sections|revid|displaytitle
  pst            - Do a pre-save transform on the input before parsing it.
                   Ignored if page or oldid is used.
  onlypst        - Do a PST on the input, but don't parse it.
                   Returns PSTed wikitext. Ignored if page or oldid is used.
Example:
  api.php?action=parse&text={{Project:Sandbox}}

来源:http://john2007.iteye.com/blog/800446