This document discusses adding external search functionality to a Django app by utilizing the Bing Search API. It describes registering for a Bing API key, building a Bing search Python module to run queries and handle the JSON response, and integrating search into the app templates and views. Special considerations for encoding queries as Unicode and handling the response are also covered.

1. TwD Chapter 12
Adding External
Search Functionality
asika Kuo
For Django Summer

2. Django Summer 2
12. Adding External Search
Functionality
●
本章要利用 Bing API 替 APP 增加搜尋功能

3. Django Summer 3
12.1. The Bing Search API
●
把用 Bing 搜尋到的資料顯示在自己的 APP 裡
●
Bing 伺服器回傳的 result 可以是 XML 或 JSON （可以自己
指定）

4. Django Summer 4
12.1.1. Registering for a Bing API Key
●
註冊 MS 的帳號（可以直接用 hotmail 的）
– https://account.windowsazure.com
●
到 Windows Azure Marketplace Bing Search API page 訂
閱免費版搜尋 API 服務
– 5,000 Transactions/month

5. Django Summer 5
12.2. Adding Search Functionality
●
建立 rango/bing_search.py

6. Django Summer 6
12.2. Adding Search Functionality
●
根據 API 的規定準備
好我們要送出的
request 字串
def run_query(search_terms):
root_url =
'https://api.datamarket.azure.com/Bing/Search/'
source = 'Web'
results_per_page = 10
offset = 0
query = "'{0}'".format(search_terms)
query = urllib.quote(query)
search_url = "{0}{1}?
$format=json&$top={2}&$skip={3}&Query={4}".format(
root_url,
source,
results_per_page,
offset,
query)

7. Django Summer 7
12.2. Adding Search Functionality
●
利用 urllib2 的
password manager
在送出的 HTTP
request header 中加
入我們剛申請好的
API Key 資訊
●
# Setup authentication with the Bing servers.
# The username MUST be a blank string, and put in
your API key!
username = ''
bing_api_key = '<api_key>'
# Create a 'password manager' which handles
authentication for us.
password_mgr =
urllib2.HTTPPasswordMgrWithDefaultRealm()
password_mgr.add_password(None, search_url,
username, bing_api_key)

8. Django Summer 8
● HTTP Basic Authentication
– 在用戶端發送 request 時一併於 HTTP header 提供用戶名和密碼的一
種簡易認證方式
– 預設會將 <username>:<password> 用 Base64 編碼後送出
●
不是為了安全性而是為了轉換掉與 HTTP 不相容的字元
●
Bing 規定的 API Key 認證方式
– Username: 空字串
– Password: 申請到的 API Key

9. Django Summer 9
12.2. Adding Search Functionality
●
用 urllib2.openurl()
連同 query string 和
認證資訊一起送出
●
接到的 response 會
是字串格式的 JSON
●
用 json.loads() 轉成
python dictionary
# Prepare for connecting to Bing's servers.
handler = urllib2.HTTPBasicAuthHandler(password_mgr)
opener = urllib2.build_opener(handler)
urllib2.install_opener(opener)
# Connect to the server and read the response generated.
response = urllib2.urlopen(search_url).read()
# Convert the string response to a Python dictionary object.
json_response = json.loads(response)
# Loop through each page returned, populating out results list.
for result in json_response['d']['results']:
results.append({
'title': result['Title'],
'link': result['Url'],
'summary': result['Description']})

10. Django Summer 10
12.3. Putting Search into Rango
●
建立
templates/rango/se
arch.html
– 如果有傳入
result_list 就把內
容 render 到頁面
上
{% if result_list %}
<!-- Display search results in an ordered list -->
<div style="clear: both;">
<ol>
{% for result in result_list %}
<li>
<strong><a
href="{{ result.link }}">{{ result.title }}</a></strong>
<br />
<em>{{ result.summary }}</em>
</li>
{% endfor %}
</ol>
</div>
{% endif %}

11. Django Summer 11
12.3.2. Adding the View
def search(request):
context = RequestContext(request)
result_list = []
if request.method == 'POST':
query = request.POST['query'].strip()
if query:
# Run our Bing function to get the
results list!
result_list = run_query(query)
return
render_to_response('rango/search.html',
{'result_list': result_list}, context)

12. Django Summer 12
處理 Unicode
● run_query() 預設處理的格式是 str
– query = "'{0}'".format(search_terms)
● 從前端傳回來的 query string 是 unicode
– 包含英文以外的字元， format() 就會發生
UnicodeEncodeError
● 解法
– 呼叫 unicode 的 format()
● query = u"'{0}'".format(search_terms)
●

13. Django Summer 13
處理 Unicode
● urllib.quote() 傳入 unicode 字串發生 KeyError
● 解法
– 把 query 字串編碼為 UTF-8
– query = urllib.quote(query.encode('utf-8'))