用 Exhibit 真正链接开放数据（2）从 Atom 到 JSON
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- UID
- 1066743
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用 Exhibit 真正链接开放数据（2）从 Atom 到 JSON
从 Atom 到 JSON有很多方式可以将 Atom 1.0 转变成 JSON，为此，已经有人编写了多个质量各异的 XSLT 脚本。我通常习惯使用 Python 代码，但幸运的是能够将非常友好的处理 XML 的库和处理 JSON 的库结合起来。前者是 Amara XML Toolkit，后者是 simplejson。是完整的脚本 (atom2json.py)，用来从 所示的 Atom 生成 Exhibit JSON。
清单 3 (atom2json.py). 将 Atom 转变成 Exhibit JSON1
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| import sys
import amara
import simplejson
#Parse Atom XML from the file name or URL given on the command line
source = sys.argv[1]
doc = amara.parse(source)
#This is a list comprehension. It iterates over the list of entry elements
#And creates a Python dictionary for each, with keys and values drawn from
#Each entry.
entries = [
#Result spec of the list comprehension
{
u"label": unicode(e.id),
u"type": u"Entry",
u"title": unicode(e.title),
#Nested list comprehension to select the alternate link,
#then select the first result ([0]) and gets its href attribute
u"link": [ l for l in e.link if l.rel == u"alternate" ][0].href,
u"author": unicode(e.author.name),
u"logo": unicode(e.logo),
#Nested list comprehension to create a list of category values
u"categories": [ unicode(c.term) for c in e.category ],
u"updated": unicode(e.updated),
u"content": unicode(e.content),
}
#Iteration spec of the list comprehension
for e in doc.feed.entry
]
exhibit_obj = {'items': entries}
#Write the result as JSON to the console
simplejson.dump(exhibit_obj, sys.stdout, indent=4)
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Amara 允许以一种很简单的方式访问 XML 文档，就如同这类文档是 Python 的一种结构一样（它也试图通过保留 XML 的基本特征来在二者之间取得均衡）。simplejson 则允许使用 Python 中的等效工具来读写 JSON，例如，用一个 Python 列表来表示 JSON 数组，或一个 Python dictionary（关联数组或哈希表类型）。(feed.js) 是 的运行结果，清单 3 可以这么调用：python atom2json.py clipart.feed.xml > feed.js。您可以使用任何自己喜欢的工具和技术来生成 JSON，这样一来，您就能尽享其中的快乐了。
清单 4 (feed.js). 由清单 3 创建的 Exhibit JSON1
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| {
"items": [
{
"updated": "2008-03-11T20:06:06+00:00",
"title": "Hard Hat",
"author": "Adriano Ribeiro",
"label": "http:\/\/openclipart.org\/media\/files\/adriano\/8006",
"content": "A yellow hard hat and a wrench",
"link": "http:\/\/openclipart.org\/media\/files\/adriano\/8006",
"logo": "http:\/\/openclipart.org\/people\/adriano\/avatar.gif",
"type": "Entry",
"categories": [
"unchecked",
"public_domain",
"image",
"tool",
"man",
"hat",
"hard",
"work",
"wrench"
]
},
{
"updated": "2008-03-11T16:45:01+00:00",
"title": "Ship's Badge",
"author": "Caggles",
"label": "http:\/\/openclipart.org\/media\/files\/Caggles\/8005",
"content": "Blank outline for a Royal Navy ship's crest. \n ",
"link": "http:\/\/openclipart.org\/media\/files\/Caggles\/8005",
"logo": "http:\/\/openclipart.org\/ccimages\/person.png",
"type": "Entry",
"categories": [
"unchecked",
"public_domain",
"image",
"svg",
"png",
"badge",
"heraldry",
"crest",
"navy",
"ship",
"insignia"
]
}
]
}
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