hhy5277/scrapy-mongodb

MongoDB pipeline for Scrapy. This module supports both MongoDB in standalone setups and replica sets. scrapy-mongodb will insert the items to MongoDB as soon as your spider finds data to extract.

scrapy-mongodb

MongoDB pipeline for Scrapy. This library supports both MongoDB in standalone setups and replica sets. It will insert items to MongoDB as soon as your spider finds data to extract. scrapy-mongodb can also buffer objects if you prefer to write chunks of data to MongoDB rather than one write per document (see MONGODB_BUFFER_DATA option for details).

INSTALLATION

Dependencies

Read more here.

Instructions

Install via pip:

pip install -r requirements.txt
pip install scrapy-mongodb

CONFIGURATION

Basic configuration

Add these options to settings.py file:

ITEM_PIPELINES = {
    ...
    'scrapy_mongodb.MongoDBPipeline': 300,
    ...
}

MONGODB_URI = 'mongodb://localhost:27017'
MONGODB_DATABASE = 'scrapy'
MONGODB_COLLECTION = 'my_items'

If you want a unique key in your database, name the key with this option:

MONGODB_UNIQUE_KEY = 'url'

Replica sets

You can configure scrapy-mongodb to support MongoDB replica sets by adding MONGODB_REPLICA_SET option and specify additional replica set hosts in MONGODB_URI:

MONGODB_REPLICA_SET = 'myReplicaSetName'
MONGODB_URI = 'mongodb://host1.example.com:27017,host2.example.com:27017,host3.example.com:27017'

If you need to ensure that your data has been replicated, use the MONGODB_REPLICA_SET_W option. It is an implementation of the w parameter in pymongo. Details from the pymongo documentation:

Write operations will block until they have been replicated to the specified number or tagged set of servers. w=<int> always includes the replica set primary (e.g. w=3 means write to the primary and wait until replicated to two secondaries). Passing w=0 disables write acknowledgement and all other write concern options.

Data buffering

To ease the load on MongoDB, scrapy-mongodb has a buffering feature. You can enable it by setting MONGODB_BUFFER_DATA to the buffer size you want. E.g: scrapy-mongodb will write 10 documents at a time to the database if you set:

MONGODB_BUFFER_DATA = 10

It is not possible to combine this feature with MONGODB_UNIQUE_KEY. Technically due to that the update method in pymongo doesn't support multi-doc updates.

Timestamps

scrapy-mongodb can append a timestamp to your item when inserting it to the database. Enable this feature with:

MONGODB_ADD_TIMESTAMP = True

This will modify the document to something like this:

{
    ...
    'scrapy-mongodb': {
        'ts': ISODate("2013-01-10T07:43:56.797Z")
    }
    ...
}

The timestamp is in UTC.

One collection per spider

It's possible to write data to 1 collection per spider. To enable that feature, set this environment variable:

MONGODB_SEPARATE_COLLECTIONS = True

Full list of available options

Parameter	Default	Required?	Description
MONGODB_DATABASE	scrapy-mongodb	No	Database to use. Does not need to exist.
MONGODB_COLLECTION	items	No	Collection within the database to use. Does not need to exist.
MONGODB_URI	mongodb://localhost:27017	No	URI to the MongoDB instance or replica sets you want to connect to. It must start with mongodb:// (see more in the MongoDB docs). E.g.: mongodb://user:pass@host:port, mongodb://user:pass@host:port,host2:port2
MONGODB_UNIQUE_KEY	None	No	If you want to have a unique key in the database, enter the key name here. scrapy-mongodb will ensure the key is properly indexed.
MONGODB_BUFFER_DATA	None	No	To ease the load on MongoDB, set this option to the number of items you want to buffer in the client before sending them to database. Setting a MONGODB_UNIQUE_KEY together with MONGODB_BUFFER_DATA is not supported.
MONGODB_ADD_TIMESTAMP	False	No	If set to True, scrapy-mongodb will add a timestamp key to the documents.
MONGODB_FSYNC	False	No	If set to True, it forces MongoDB to wait for all files to be synced before returning.
MONGODB_REPLICA_SET	None	Yes, for replica sets	Set this if you want to enable replica set support. The option should be given the name of the replica sets you want to connect to. MONGODB_URI should point at your config servers.
MONGODB_REPLICA_SET_W	0	No	Best described in the pymongo docs. Write operations will block until they have been replicated to the specified number or tagged set of servers. w=<int> always includes the replica set primary (e.g. w=3 means write to the primary and wait until replicated to two secondaries). Passing w=0 disables write acknowledgement and all other write concern options.
MONGODB_STOP_ON_DUPLICATE	0	No	Set this to a value greater than 0 to close the spider when that number of duplicated insertions in MongoDB are detected. If set to 0, this option has no effect.

Deprecated options

Since scrapy-mongodb 0.5.0

Parameter	Default	Required?	Description
MONGODB_HOST	localhost	No	MongoDB host name to connect to. Use MONGODB_URI instead.
MONGODB_PORT	27017	No	MongoDB port number to connect to. Use MONGODB_URI instead.
MONGODB_REPLICA_SET_HOSTS	None	No	Host string to use to connect to the replica set. See the hosts_or_uri option in the pymongo docs. Use MONGODB_URI instead.

PUBLISHING TO PYPI

make release

CHANGELOG

Read more here.

AUTHOR

This project is maintained by: Sebastian Dahlgren (GitHub | Twitter | LinkedIn).

LICENSE

Read more here.