scrapy-item-pipelines 0.2

Collection of reusable scrapy item pipelines

scrapy-item-pipelines

Various scrapy item pipelines

Installation

pip install scrapy-item-pipelines

SaveToKafkaPipeline

Item pipeline to push items to kafka. Items will be converted into JSON format and pushed to a defined kafka topic.

Settings

SL_SCRAPY_ITEM_PIPELINES_SETTINGS = {
    "push_to_kafka_hosts": "localhost:9092"  # Kafka broker hosts. Separated with a comma.
    "push_to_kafka_default_topic": ""  # kafka default topic.
}

Usage

If items should be pushed to different kafka topics per item, the topic can be defined in the item class. Also if a data key should be pushed to kafka we can define the item field value to use by defining it in the item class. If no kafka_data_key is defined no data key will be pushed.

class DemoItem(scrapy.Item):
    kafka_topic = "topic-to-push-items"
    kafka_data_key = "another_unique_field"

    field_name = scrapy.Field()
    another_unique_field = scrapy.Field()

After configuring add scrapy_item_pipelines.streaming.PushToKafkaPipeline to the ITEM_PIPELINES setting.

ITEM_PIPELINES = {
    ...
    ...
    "scrapy_item_pipelines.streaming.PushToKafkaPipeline": 999,
}

FilterDuplicatesPipeline

Item pipeline to filter out duplicate items calculated using defined keys in the item.

Usage

Define an attribute called unique_key in the item. If the unique key is a single field unique_key can be defined as a string or if the unique key is a multi field key unique_key should be a tuple of strings. If no unique_key is defined filtering will be done using id field. If you want to skip duplicate filtering for an item define unique_key as None.

The pipeline will include a stats called duplicate_item_count which is the number of duplicate items dropped.

class DemoItem(scrapy.Item):
    field1 = scrapy.Field()
    field2 = scrapy.Field()

    unique_key = None  # duplicates won't be filtered.


class DemoItem(scrapy.Item):
    # No unique_key is defined. Filtering will be done using `id` field.
    field1 = scrapy.Field()
    field2 = scrapy.Field()
    id = scrapy.Field()


class DemoItem(scrapy.Item):
    field1 = scrapy.Field()
    field2 = scrapy.Field()

    unique_key = "field1"  # Duplicates will be filtered using field1.


class DemoItem(scrapy.Item):
    field1 = scrapy.Field()
    field2 = scrapy.Field()

    unique_key = ("field1", "field2")  # Duplicates will be filtered using both field1 and field2

Add scrapy_item_pipelines.misc.FilterDuplicatesPipeline to the ITEM_PIPELINES setting.

ITEM_PIPELINES = {
    ...
    ...
    "scrapy_item_pipelines.misc.FilterDuplicatesPipeline": 500,
}