saving picture to mongodb

问题:

am trying yo do this using tornado and pil and mongodb.

avat = self.request.files['avatar'][0]["body"]
nomfich = self.request.files['avatar'][0]["filename"]

try:
    image = Image.open(StringIO.StringIO(buf=avat))
    size = image.size
    type = image.format

    avatar = r"/profile-images/{0}/{1}".format(pseudo, nomfich)

except IOError:
    self.redirect("/erreur-im")

and the database code:

user={
    "pseudo": pseudo, 
    "password":password, 
    "email":email, 
    "tel":tel, 
    "commune":commune,    
    "statut":statut, 
    "nom":nom, 
    "prenom":prenom, 
    "daten":daten, 
    "sexe":sexe, 
    "avatar":avatar
}

self.db.essog.insert(user)  

and it worked ok, the "avatar" is saved, but there in no image, it saves only a name!

my problem is:

• to understand how database deals with pictures, must i make image.save(path, format), but the path, is it a path of a normal system path (windows, or linux)?
• the profile is simple, and i've limited the picture upload to 500ko, and the document in mongodb is 16mb, so the document will handle the entire profile, but must i use gridFS even for small document when it contains picture? the key problem is in path of the picture saving, am stuck, and it's the first time i deal with database, so am sorry for that question.

回答1:

You don't necessarily need GridFS for storing files in MongoDB, but it surely makes it a nicer experience, because it handles the splitting and saving of the binary data, while making the metadata also available. You can then store an ID in your User document to the avatar picture.

That aside, you could also store binary data directly in your documents, though in your code you are not saving the data. You simply are opening it with PIL.Image, but then doing nothing with it.

Assuming you are using pymongo for your driver, I think what you can do is just wrap the binary data in a Binary container, and then store it. This is untested by me, but I assume it should work:

from pymongo.binary import Binary

binary_avatar = Binary(avat)

user={
    ...
    "avatar":avatar,
    "avatar_file": binary_avatar
    ...
}

Now that being said... just make it easier on yourself and use GridFS. That is what it is meant for.

If you were to use GridFS, it might look like this:

from gridfs import GridFS

avat_ctype = self.request.files['avatar'][0]["content_type"]

fs = GridFS(db)
avatar_id = fs.put(avat, content_type=avat_ctype, filename=nomfich)

user={
    ...
    "avatar_name":avatar,
    "avatar_id": avatar_id
    ...
}

回答2:

This is the code to insert and retrieve image in mongodb without using gridfs.

def insert_image(request):
    with open(request.GET["image_name"], "rb") as image_file:
        encoded_string = base64.b64encode(image_file.read())
    print encoded_string
    abc=db.database_name.insert({"image":encoded_string})
    return HttpResponse("inserted")

def retrieve_image(request):
    data = db.database_name.find()
    data1 = json.loads(dumps(data))
    img = data1[0]
    img1 = img['image']
    decode=img1.decode()
    img_tag = '<img alt="sample" src="data:image/png;base64,{0}">'.format(decode)
    return HttpResponse(img_tag)

回答3:

there is an error in :

          from pymongo.binary import Binary

the correct syntax is:

          from bson.binary import Binary

thk you all for your endless support

Luca

回答4:

Try using carierwave-mongoid https://github.com/jnicklas/carrierwave-mongoid I think it is a simple and easy way for you in this case

回答5:

You need to save binary data using the Binary() datatype of pymongo.

http://api.mongodb.org/python/2.0/api/bson/binary.html#module-bson.binary