網頁中遇到的src="data:image/png;base64,xxxx"知識點了解

    在學爬蟲中,總是習慣去找網上圖片的url,但是你一定會遇到我題目說說的問題。網頁上有些圖片的src或css背景圖片的url後面跟了一大串字符,比如:

data:image/png;base64,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
        那麼這是什麼呢?這是Data URI scheme。
        Data URI scheme是在RFC2397中定義的,目的是將一些小的數據,直接嵌入到網頁中,從而不用再從外部文件載入。比如上面那串字符,其實是一張小圖片,將這些字符複製黏貼到瀏覽器的地址欄中並轉到,就能看到它了,也就是我的頭像。^_^
在上面的Data URI中,data表示取得數據的協定名稱,image/png 是數據類型名稱,base64 是數據的編碼方法,
        逗號後面就是這個image/png文件base64編碼後的數據。

        目前,Data URI scheme支持的類型有:

data:,文本數據
data:text/plain,文本數據
data:text/html,HTML代碼
data:text/html;base64,base64編碼的HTML代碼
data:text/css,CSS代碼
data:text/css;base64,base64編碼的CSS代碼
data:text/javascript,Javascript代碼
data:text/javascript;base64,base64編碼的Javascript代碼
data:image/gif;base64,base64編碼的gif圖片數據
data:image/png;base64,base64編碼的png圖片數據
data:image/jpeg;base64,base64編碼的jpeg圖片數據

data:image/x-icon;base64,base64編碼的icon圖片數據

    base64簡單地說,它把一些 8-bit 數據翻譯成標準 ASCII 字符,網上有很多免費的base64 編碼和解碼的工具,在目前,IE8、Firfox、Chrome、Opera瀏覽器都支持這種小文件嵌入。

關於base64編碼如下:

    測試例子,把文字轉成base64編碼

>>> import base64
>>> ls_s='字符串文本'
>>> ls_t=base64.b64encode(ls_s) #轉換文本內容到base64
>>> print ls_t
19a3+7SuzsSxvg==
>>> print base64.b64decode(ls_t) #解碼
字符串文本
>>>
# 把圖片內容轉成base64編碼
import base64
f=open(r'x:\1.jpg','rb') #二進制方式打開圖文件
ls_f=base64.b64encode(f.read()) #讀取文件內容,轉換爲base64編碼 
f.close()

把編碼文本寫入一個txt文件
fw=open(r'x:\1.txt','w') #打開一個空白文本文件,準備寫入
fw.write(ls_f)
fw.flush()
fw.close()
網頁的表達
<html><body><img src="data:image/jpeg;base64,這裏放的是上面寫入的1.txt 的內容" /></body></html>
*注意 image/jpeg 如果圖片是其它類型的,這裏也要修改; image/png、image/gif、image/bmp 等
data: URI定義於IETF標準的RFC 2397 
data: URI的基本使用格式如下: 

data:[<MIME-type>][;base64|charset=some_charset],<data> 

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