CODEWITHSUNDEEP
pythonmongodbweb2pyobjectid
datasci
datasci

Reputation: 1029

MongoDB & web2py: Working with ObjectIds

I'm working on a very simple application as a use case for integrating MongoDB with web2py. In one section of the application, I'm interested in returning a list of products:

My database table:

db.define_table('products',
Field('brand', label='Brand'),
Field('photo', label='Photo'),
...
Field('options', label='Options'))

My controller: 

def products():
qset = db(db['products'])
grid = qset.select()
return dict(grid=grid)

My view: 

{{extend 'layout.html'}}
<h2>Product List</h2>
{{=grid}}

The products are returned without issue. However, the products._id field returns values in the form '26086541625969213357181461154'. If I switch to the shell (or python) and attempt to query my database based on those _ids, I can't find any of the products.

As you would expect, the _ids in the database are ObjectIds that look like this '544a481b2ceb7c3093a173a2'. I'd like to my view to return the ObjectIds and not the long strings. Simple, but I'm having trouble with it.

Upvotes: 1

Views: 1119

Answers (2)

datasci
datasci

Reputation: 1029

Although it makes perfect sense, I wasn't able to make Anthony's answer work. So, I just hacked it:

hex(value).replace("0x","").replace("L","")

Upvotes: 1

Anthony
Anthony

Reputation: 25536

When constructing the DAL Row object for a given MongoDB record, the ObjectId is represented by converting to a long integer via long(str(value), 16). To convert back to an ObjectId, you can use the object_id method of the MongoDB adapter:

object_id = db._adapter.object_id('26086541625969213357181461154')

Of course, if you use the DAL to query MongoDB, you don't have to worry about this, as it handles the conversion automatically.

Upvotes: 1

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