mongodb python image 图像存储读取

来源：互联网发布：ubuntu文件大小怎么看编辑：程序博客网时间：2024/05/16 10:32

最近做一些数据库调研的工作，目标是实现影像更快的入库、出库、查询，并实现并行访问等操作。

将结果总结成一个mongoImg类，也算是小结吧。

 1 ''' 2 Created on 2013-8-6 3 class mongoInsert 4 @author: tree 5 ''' 6 __metaclass__ = type 7  8 import os 9 from pymongo.database import Database10 import time11 import gridfs12 13 class mongoImg(object):14     """mongoInsert is a class for inserting document15     16     17     """18     def __init__(self, database, dir):19         """Create a new instance of :class:mongoInsert20         :Parameters:21           - `database`: database to use22           - `dir` : directory of document 23           """24         if not isinstance(database, Database):25             raise TypeError("database must be an instance of Database")26         if len(dir) < 1:27             raise TypeError("dir must be an string of directory")28         29 #         self.__con = Connection()30         self.__imgdb = database31         self.__imgfs = gridfs.GridFS (self.__imgdb)32         self.__dir = dir33         self.__filelist=[]34 35     #save filepath in list.txt36     def __dirwalk(self,topdown=True):37         """traverse the documents of self.__dir and save in self.__filelist38         """39         sum=040         self.__filelist.clear()41         42         for root,dirs,files in os.walk(self.__dir,topdown):43             for name in files:44                 sum+=145                 temp=os.path.join(root,name)46                 self.__filelist.append(temp)47         print(sum)48 49     #insert image 50     def insert(self):51         """insert images in mongodb52         """53         self.__dirwalk()54 55         tStart = time.time()        56         for fi in self.__filelist:       57             with open (fi,'rb') as myimage:58                 data=myimage.read()                  59                 self.__imgfs.put(data, content_type = "jpg", filename =fi)60     61         tEnd =time.time ()62         print ("It cost %f sec" % (tEnd - tStart))63         64     #get image by filename65     def getbyname(self,filename,savepath):66         """get img from mongdb by filename67         """68         if len(savepath) < 1:69             raise TypeError("dir must be an string of directory")70         dataout=self.__imgfs.get_version(filename)71         try:72             imgout=open(savepath,'wb')73             data=dataout.read()74             imgout.write(data)75         finally:76             imgout.close()77

使用示例：也可以将数据库连接写在类内部

1 from pymongo import Connection2 import mongoImg3 4 filedir=r'D:\image'5 con = Connection()6 db = con.imgdb7 imgmongo=mongoImg.mongoImg(db,filedir)8 imgmongo.insert()

感觉mongodb存储影像切片还是蛮快的，1w多个图片，大约100-200秒左右。

tip：

gridfs.GridFS.put 函数

put(data, **kwargs)Put data in GridFS as a new file.Equivalent to doing:try:    f = new_file(**kwargs)    f.write(data)    finallyf.close()

在存储读取图像时，犯了低级错误，将open得到的file实例当做数据存储，读取的时候怎么也读不出数据。。。囧

另外以字节流形式读取图像数据比较适合。

pipe = open('/dev/input/js0','rb')

如果以str形式存储的话，可能会出现UnicodeDecodeError错误，貌似是因为图像数据有些超出了python默认编码的存储区间。

ps：初学python 数据库操作也忘得差不多欢迎大家批评和指正~

0 0