折腾：
【已解决】Flask中连接远程MongoDB数据库的gridfs并返回查询到的文件数据
期间，用代码去find：
mongoDb = mongo.db
log.info("mongoDb=%s", mongoDb)
gridfsDb = mongoDb.gridfs
log.info("gridfsDb=%s", gridfsDb)
sleepFile = gridfsDb.fs.find({"name": "sleep"})
log.info("sleepFile=%s", sleepFile)
但是调试看到的是cursor，并不是以为的一个list：
所以需要搞清楚，如何才能获得返回的文件的dict的list
看到：
提到了：
““find_one()”方法返回的就是一个字典，所以我们可以直接对其作操作。”find()”方法返回的其实是一个”pymongo.cursor.Cursor”对象，不过Cursor类实现了”__iter__()”和”next()”方法，因此可以用”for … in …”循环来遍历它。”
再去看看：
cursor – Tools for iterating over MongoDB query results — PyMongo 3.6.1 documentation
先试试count，不会这里find到的是0吧？
果然是0:
我说find不到呢。
估计是自己参数传递错了
看数据库，则是：
去搜filename才可以
但是通过工具发现：
要全名匹配才可以：
否则部分文件名去搜，返回是空的：
所以要再去搞清楚：
Mongo中如何搜索部分文件名
gridfs search part filename
gridfs search file by filename
mongodb – Ruby GridFS – Search on filename – Stack Overflow
mongo search file by filename
mongo gridfs find
python mongo gridfs find
gridfs – Tools for working with GridFS — PyMongo 2.8 documentation
好像没有根据文件名的模糊搜索
python mongo gridfs wildcard find
mongodb – Performing regex Queries with pymongo – Stack Overflow
去试试regex，结果还是找不到文件：
python – REGEX Searching in pymongo – Stack Overflow
好像是有问题的，需要用$regex才可以
还是不行：
才发现，是数据库的collection搞错了：
结果：
竟然还是0:
结果：
gridfsDb = mongoDb.gridfs
log.info("gridfsDb=%s", gridfsDb)
# fsCollection = GridFS(gridfsDb)
# log.info("fsCollection=%s", fsCollection)
findRegex = re.compile("Go", re.IGNORECASE)
log.info("findRegex=%s", findRegex)
# findFileCursor = gridfsDb.fs.find({"filename": findRegex})
# findFileCursor = gridfsDb.fs.find({"filename": {"$regex": findRegex, "$options": "i"}})
# findFileCursor = gridfsDb.fs.find({"filename": {"$regex": "Go", "$options": "i"}})
# findFileCursor = gridfsDb.fs.find({"filename": {"$regex": "Go"}})
# findFileCursor = gridfsDb.fs.files.find({"filename": {"$regex": "Go"}})
# findFileCursor = gridfsDb.fs.files.find({"filename": "Go away, Mr Wolf.mp3"})
# findFileCursor = gridfsDb.fs.files.find({"filename": "Go away, Mr Wolf.mp3"})
findFileCursor = gridfsDb.fs.files.find()
log.info("findFileCursor=%s", findFileCursor)
findFileCount = findFileCursor.count()
log.info("findFileCount=%s", findFileCount)
竟然都还是0:
看来肯定是哪里搞错了。
python mongo gridfs can not find filename
结果试了多次，（在别的项目中可以工作的mongod的gridfs的）代码：
# fsCollection = gridfsDb.fs
# fsCollection = gridfsDb["fs"]
fsCollection = GridFS(gridfsDb)
logging.info("fsCollection=%s", fsCollection)
# findFileCursor = fsCollection.files.find()
# findFileCursor = fsCollection.files.find_one()
# findFileCursor = fsCollection.files.find_one()
findFileCursor = fsCollection.find_one()
# findFileCursor = fsCollection.find()
log.info("findFileCursor=%s", findFileCursor)
findFileCount = findFileCursor.count()
log.info("findFileCount=%s", findFileCount)
还出错：
File "/Users/crifan/dev/dev_root/company/naturling/projects/robotDemo/testRestApi.py", line 89, in get
fsCollection = GridFS(gridfsDb)
File "/Users/crifan/.virtualenvs/robotDemo-HXjMJQEQ/lib/python3.6/site-packages/gridfs/__init__.py", line 59, in __init__
raise TypeError("database must be an instance of Database")
TypeError: database must be an instance of Database
pymongo gridfs
Flask-PyMongo gridfs find
Just a little Python: GridFS: The MongoDB Filesystem
Flask-PyMongo — Flask-PyMongo 0.5.1 documentation
Flask-PyMongo — Flask-PyMongo 0.4.0 documentation
然后发现：
此处的gridfs，不论是fs还是fs.files的fine_one，都是None
感觉是：flask-pymongo 有问题？
和我直接用pymongo有啥区别？
flask-pymongo vs pymongo
python – Difference between PyMongo and Flask-PyMongo libraries – Stack Overflow
好像没啥多大好处
Python Tutorial: MongoDB RESTful API with Flask – 2018
python – PyMongo on the Flask – Stack Overflow
mongodb – What is the relationship between flask, mongokit, pymongo, flask-pymongo? – Stack Overflow
database – What is the difference between an ORM and an ODM? – Stack Overflow
MongoDB Flaskers, what’s your opinion on Ming vs MongoEngine vs directly using PyMongo?：flask
How Do You Use MongoDB With Python?
大家用什么 MongoDB 的 ORM 来配合 Flask – V2EX
Tools — PyMongo 2.7 documentation
算了，去单独使用pymono试试
# pure use pymongo
gridfsDb2 = mongoClient.gridfs
logging.info("gridfsDb2=%s", gridfsDb2)
fsCollection2 = GridFS(gridfsDb2)
logging.info("fsCollection2=%s", fsCollection2)
findFileCursor = fsCollection2.find()
log.info("findFileCursor=%s", findFileCursor)
findFileCount = findFileCursor.count()
log.info("findFileCount=%s", findFileCount)
然后就是可以搜索到文件的：
然后相关代码：
# mongoClient = MongoClient(mongodbUri)
mongoClient = MongoClient(
host=“x.x.x.x",
port=xxxx,
username="gridfs",
password=“yyy",
authSource="gridfs"
)
log.info("mongoClient=%s", mongoClient)
# pure use pymongo
gridfsDb2 = mongoClient.gridfs
logging.info("gridfsDb2=%s", gridfsDb2)
fsCollection2 = GridFS(gridfsDb2)
logging.info("fsCollection2=%s", fsCollection2)
# findFileCursor = fsCollection2.find()
findFileCursor = fsCollection2.find({"filename": {"$regex": "sleep", "$options": "i"}})
log.info("findFileCursor=%s", findFileCursor)
findFileCount = findFileCursor.count()
log.info("findFileCount=%s", findFileCount)
for curIdx, eachFile in enumerate(findFileCursor):
curNum = curIdx + 1
log.info("[%d] _id=%s, filename=%s", curNum, eachFile._id, eachFile.filename)
再去调试，就可以找到文件了：
那看起来是：
要么是我自己不会用flask-pymongo
要么是flask-pymongo有问题？
flask-pymongo not work
flask-pymongo not work find none
flask-pymongo not work
此处经过调试代码：
app.config.update(
MONGO_HOST=‘xxx’,
MONGO_PORT=xxx,
MONGO_USERNAME=’gridfs’,
MONGO_PASSWORD=‘xxx’,
MONGO_DBNAME=’gridfs’
)
flaskPymongo = PyMongo(app)
log.info("flaskPymongo=%s", flaskPymongo)
# purePymongo = MongoClient(mongodbUri)
purePymongo = MongoClient(
host=“xxx",
port=xx,
username="gridfs",
password=“xxx",
authSource="gridfs"
)
log.info("purePymongo=%s", purePymongo)
# Flask-PyMongo
mongoDb = flaskPymongo.db #Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’)
log.info("mongoDb=%s", mongoDb)
gridfsDb = mongoDb.gridfs #Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs’)
log.info("gridfsDb=%s", gridfsDb)
fsCollection = gridfsDb.fs #Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs.fs’)
log.info("fsCollection=%s", fsCollection)
filesCollection = fsCollection.files # Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs.fs.files’)
log.info("filesCollection=%s", filesCollection)
# # Pure PyMongo
# gridfsDb = purePymongo.gridfs #Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’), ‘gridfs’)
# logging.info("gridfsDb=%s", gridfsDb)
# fsCollection = GridFS(gridfsDb) #<gridfs.GridFS object at 0x1107b2390>
# logging.info("fsCollection=%s", fsCollection)
fsFindOne = fsCollection.find_one() #<gridfs.grid_file.GridOut object at 0x110a87fd0>
log.info("fsFindOne=%s", fsFindOne)
filesFindOne = filesCollection.find_one()
log.info("filesFindOne=%s", filesFindOne)
发现：
Flask-PyMongo得到的fs或fs.file的Collection去fine_one，都是None
而纯的PyMongo得到的fs的Collection去fine_one，就可以find到文件
看起来像是：flask-pymongo中，对于gridfs本身支持有问题？
flask-pymongo gridfs
share/access db connection · Issue #101 · dcrosta/flask-pymongo
A simple GridFS server built with Flask
flask-pymongo 不支持 gridfs
去试了试grifs的fine_one也是None：
gridFineOne = gridfsDb.find_one() #
log.info("gridFineOne=%s", gridFineOne)
算了，找不到相关的内容
就不继续折腾了。
【总结】
此处Flask-PyMongo，对于gridfs来说，不论是gridfs，还是gridfs.fs，还是grifs.fs.files，都无法通过find或fine_one去找到文件。搞不清楚为何。
最后只能用纯的PyMongo才可以。
具体代码：
# from flask_pymongo import PyMongo
from gridfs import GridFS
from pymongo import MongoClient
# Flask-PyMongo NOT work: gridfs can NOT find files
# app.config.update(
# MONGO_HOST=’x.x.x.x‘,
# MONGO_PORT=12345,
# MONGO_USERNAME=’gridfs’,
# MONGO_PASSWORD=’P@wd’,
# MONGO_DBNAME=’gridfs’
# )
# flaskPymongo = PyMongo(app)
# log.info("flaskPymongo=%s", flaskPymongo)
# purePymongo = MongoClient(mongodbUri)
purePymongo = MongoClient(
host="x.x.x.x",
port=12345,
username="gridfs",
password=“xxx",
authSource="gridfs"
)
log.info("purePymongo=%s", purePymongo)
# # Flask-PyMongo
# mongoDb = flaskPymongo.db #Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’)
# log.info("mongoDb=%s", mongoDb)
# gridfsDb = mongoDb.gridfs #Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs’)
# log.info("gridfsDb=%s", gridfsDb)
# fsCollection = gridfsDb.fs #Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs.fs’)
# log.info("fsCollection=%s", fsCollection)
# filesCollection = fsCollection.files # Collection(Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=True, connect=True, replicaset=None), ‘gridfs’), ‘gridfs.fs.files’)
# log.info("filesCollection=%s", filesCollection)
# Pure PyMongo
gridfsDb = purePymongo.gridfs #Database(MongoClient(host=[‘x.x.x.x:12345‘], document_class=dict, tz_aware=False, connect=True, authsource=’gridfs’), ‘gridfs’)
logging.info("gridfsDb=%s", gridfsDb)
fsCollection = GridFS(gridfsDb) #<gridfs.GridFS object at 0x1107b2390>
logging.info("fsCollection=%s", fsCollection)
fsFindOne = fsCollection.find_one() #<gridfs.grid_file.GridOut object at 0x110a87fd0>
log.info("fsFindOne=%s", fsFindOne)
# gridFineOne = gridfsDb.find_one() #
# log.info("gridFineOne=%s", gridFineOne)
#
# filesFindOne = filesCollection.find_one()
# log.info("filesFindOne=%s", filesFindOne)
# findRegex = re.compile("Go", re.IGNORECASE)
findRegex = re.compile("sleep", re.IGNORECASE)
log.info("findRegex=%s", findRegex)
# findFileCursor = gridfsDb.fs.find({"filename": findRegex})
# findFileCursor = gridfsDb.fs.find({"filename": {"$regex": findRegex, "$options": "i"}})
# findFileCursor = fsCollection.find({"filename": {"$regex": "sleep"}})
findFileCursor = fsCollection.find({"filename": {"$regex": "sleep", "$options": "i"}})
log.info("findFileCursor=%s", findFileCursor)
findFileCount = findFileCursor.count()
log.info("findFileCount=%s", findFileCount)
for curIdx, eachFile in enumerate(findFileCursor):
curNum = curIdx + 1
log.info("[%d] _id=%s, filename=%s", curNum, eachFile._id, eachFile.filename)
效果：
注：
（1）此处另外两种写法：
findRegex = re.compile("sleep", re.IGNORECASE)
log.info("findRegex=%s", findRegex)
# findFileCursor = gridfsDb.fs.find({"filename": findRegex})
# findFileCursor = gridfsDb.fs.find({"filename": {"$regex": findRegex, "$options": "i"}})
都是不行的。
（2）此处单独搜索sleep，如果区分大小写，-》即不加i=ignore up lower case参数的话：
由于gridfs中两个文件：
filename=1004 Horrid Henry’s Sleepover.mp3
filename=2.Good Night, Sleep Tight.m4a
都没有包含sleep
所以就搜不到文件了，搜出来是None了：
