python gridfs_【已解决】用Python去连接本地mongoDB去用GridFS保存文件
折腾：
期间，命令行方式的mongofiles去put get delete delete_id等，已经基本上搞清楚了。
接着就是去用Python代码，通过driver：
的方式，调用API，去保存数据了。
python mongodb gridfs
需要先安装：pymongo
就是这些API了。
通过：
发现，
对于此处：➜ 英语资源 mongod --version
db version v3.6.3
git version: 9586e557d54ef70f9ca4b43c26892cd55257e1a5
OpenSSL version: OpenSSL 1.0.2o 27 Mar 2018
allocator: system
modules: none
build environment:
distarch: x86_64
target_arch: x86_64
➜ 英语资源 python -V
Python 2.7.13
来说，最新的3.5的Python Driver(虽然只写了MongoDB 3.4)，应该也只支持最新的MongoDB 3.6.3的
3.6的Python Driver，确定是支持的MongoDB 3.6的
另外对于Async Driver的Motor暂时不是很清楚，等用到了再说。
看到：
好像是主要是用于异步环境的，支持Tornado or asyncio
另外还有一些工具：ORM Like Layers：如果需要data validation，associations，其他high-level data modeling functionality，可以考虑用PyMODM
Humongolus
Ming
MongoEngine
MotorEngine
uMongoDjongo
Django MongoDB Engine
mango
Django MongoEngine
mongodb_beaker
Log4Mongo
MongoLog
c5t
rod.recipe.mongodb
repoze-what-plugins-mongodb
mongobox
Flask-MongoAlchemy
Flask-MongoKit
Flask-PyMongo看起来人气最旺Motor
TxMongo
MongoMock
一些教程和资料：
目前还是继续参考：
去试试吧
先去安装：➜ 英语资源 pip install pymongo
Collecting pymongo
Downloading pymongo-3.6.1-cp27-cp27m-macosx_10_13_intel.whl (310kB)
100% |████████████████████████████████| 317kB 67kB/s
Installing collected packages: pymongo
Successfully installed pymongo-3.6.1
➜ 英语资源 pip install pymongo
Requirement already satisfied: pymongo in /usr/local/lib/python2.7/site-packages
➜ 英语资源 pip install --upgrade pymongo
Requirement already up-to-date: pymongo in /usr/local/lib/python2.7/site-packages
然后
然后去Python命令行中测试：➜ 英语资源 python
Python 2.7.13 (default, May 6 2017, 15:08:03)
[GCC 4.2.1 Compatible Apple LLVM 8.1.0 (clang-802.0.38)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymongo
>>> from pymongo import MongoClient
>>> client = MongoClient()
>>>
mongod中的输出是：2018-03-29T11:14:13.462+0800 I NETWORK [listener] connection accepted from 127.0.0.1:54229 #51 (2 connections now open)
2018-03-29T11:14:13.466+0800 I NETWORK [conn51] end connection 127.0.0.1:54229 (1 connection now open)
2018-03-29T11:42:26.689+0800 I NETWORK [listener] connection accepted from 127.0.0.1:65262 #52 (2 connections now open)
2018-03-29T11:42:26.690+0800 I NETWORK [conn52] received client metadata from 127.0.0.1:65262 conn: { driver: { name: "PyMongo", version: "3.6.1" }, os: { type: "Darwin", name: "Darwin", architecture: "x86_64", version: "10.13.3" }, platform: "CPython 2.7.13.final.0" }
自己随便试了试：>>> client.gridfs
Database(MongoClient(host=['localhost:27017'], document_class=dict, tz_aware=False, connect=True), u'gridfs')
>>> client.gridfs.fs.find()
去看api
然后终于可以找到一些数据了：>>> client.gridfs.fs.findOne()
Traceback (most recent call last):
File "
File "/usr/local/lib/python2.7/site-packages/pymongo/collection.py", line 3104, in __call__
self.__name.split(".")[-1])
TypeError: 'Collection' object is not callable. If you meant to call the 'findOne' method on a 'Collection' object it is failing because no such method exists.
>>> client.gridfs.fs.find_one()
>>> client.gridfs.files.find_one()
>>> client.gridfs.fs.files.find_one()
{u'contentType': u'audio/mpeg', u'chunkSize': 261120, u'filename': u'Otto the Cat-withMIME.MP3', u'length': 8338105, u'uploadDate': datetime.datetime(2018, 3, 29, 1, 38, 44, 853000), u'_id': ObjectId('5abc43a4a4bc712159a35cd9'), u'md5': u'b7660d833085e9e1a21813e4d74b0cc3'}
>>> import pprint
>>> pprint.pprint(client.gridfs.fs.files.find_one())
{u'_id': ObjectId('5abc43a4a4bc712159a35cd9'),
u'chunkSize': 261120,
u'contentType': u'audio/mpeg',
u'filename': u'Otto the Cat-withMIME.MP3',
u'length': 8338105,
u'md5': u'b7660d833085e9e1a21813e4d74b0cc3',
u'uploadDate': datetime.datetime(2018, 3, 29, 1, 38, 44, 853000)}
证明了此处可以正常连接MongoDB，接着就可以去写代码，调试保存，读取，和删除了。
换用PyCharm去写代码和调试：
接着调试put等操作：
然后想办法添加额外参数，包括MIME，其他参数等等
注意到：
The gridfs package is an implementation of GridFS on top of pymongo, exposing a file-like interface.
gridfs这个库，是在pymongo之上，实现了GridFS这个协议，提供了类似于文件操作的接口
通过：
class gridfs.GridFS(database, collection=’fs’)¶
所以需要：
import gridfs
from gridfs import GridFS
然后后续使用：
fsCollection = GridFS(gridfsDb)
去创建对应的collection
另外去找找，上次和本地调试，保存的文件是一样：
内部是否override，还是新生成文件了
结果是：不是override，是新保存文件的：{
"_id" : ObjectId("5abc9525a4bc715e187c6d6d"),
"contentType" : "application/mpeg",
"chunkSize" : 261120,
"metadata" : {
"keywords" : {
"name" : "Lots of Hearts",
"series" : "All Aboard Reading",
"topic" : "",
"contentKeywords" : [ ],
"leadingActor" : "",
"keywords" : [
"hearts"
]
},
"isFiction" : false,
"fitAgeStartYear" : 3,
"fitAgeEndYear" : 6
},
"filename" : "Lots of Hearts_withContentType.mp3",
"length" : 4795707,
"uploadDate" : ISODate("2018-03-29T07:26:29.264Z"),
"md5" : "955d19f230a5824e0fd5f41bee3dda21"
}
{
"_id" : ObjectId("5abc96dfa4bc715f473f0297"),
"contentType" : "application/mpeg",
"chunkSize" : 261120,
"metadata" : {
"keywords" : {
"name" : "Lots of Hearts",
"series" : "All Aboard Reading",
"topic" : "",
"contentKeywords" : [ ],
"leadingActor" : "",
"keywords" : [
"hearts"
]
},
"isFiction" : false,
"fitAgeStartYear" : 3,
"fitAgeEndYear" : 6
},
"filename" : "Lots of Hearts_withContentType.mp3",
"length" : 4795707,
"uploadDate" : ISODate("2018-03-29T07:33:51.573Z"),
"md5" : "955d19f230a5824e0fd5f41bee3dda21"
}
然后去删除掉其中一个试试：
另外：
也提到了，对于API去保存文件时，没有override，会保存多份同名的内容：
只是id和uploadDate不同而已。
之所以这么做，是为了可以保存同名文件的多个版本。
而想要获取最新版本可以用：f = fs.get_last_version(filename="mystory.txt")