scrapinghub-autoextract 0.3.0

Command-line interface

The most basic way to use the client is from a command line. First, create a file with urls, an URL per line (e.g. urls.txt). Second, set SCRAPINGHUB_AUTOEXTRACT_KEY env variable with your AutoExtract API key (you can also pass API key as --api-key script argument).

Then run a script, to get the results:

python -m autoextract urls.txt --page-type article --output res.jl

If you need more flexibility, you can customize the requests by creating a JsonLines file with queries: a JSON object per line. You can pass any AutoExtract options there. Example - store it in queries.jl file:

{"url": "http://example.com", "meta": "id0", "articleBodyRaw": false}
{"url": "http://example.com/foo", "meta": "id1", "articleBodyRaw": false}
{"url": "http://example.com/bar", "meta": "id2", "articleBodyRaw": false}

See API docs for a description of all supported parameters in these query dicts. API docs mention batch requests and their limitation (no more than 100 queries at time); these limits don’t apply to the queries.jl file (i.e. it may have millions of rows), as the command-line script does its own batching.

Note that in the example pageType argument is omitted; pageType values are filled automatically from --page-type command line argument value. You can also set a different pageType for a row in queries.jl file; it has a priority over --page-type passed in cmdline.

To get results for this queries.jl file, run:

python -m autoextract --intype jl queries.jl --page-type article --output res.jl

python -m autoextract urls.txt --page-type articles --n-conn 15 --batch-size 2 --output res.jl

python -m autoextract urls.txt --page-type articles --max-query-error-retries 3 --output res.jl

Synchronous API

Synchronous API provides an easy way to try AutoExtract. For production usage asyncio API is strongly recommended. Currently the synchronous API doesn’t handle throttling errors, and has other limitations; it is most suited for quickly checking extraction results for a few URLs.

To send a request, use request_raw function; consult with the API docs to understand how to populate the query:

from autoextract.sync import request_raw
query = [{'url': 'http://example.com.foo', 'pageType': 'article'}]
results = request_raw(query)

Note that if there are several URLs in the query, results can be returned in arbitrary order.

There is also a autoextract.sync.request_batch helper, which accepts URLs and page type, and ensures results are in the same order as requested URLs:

from autoextract.sync import request_batch
urls = ['http://example.com/foo', 'http://example.com/bar']
results = request_batch(urls, page_type='article')

asyncio API

Basic usage is similar to the sync API (request_raw), but asyncio event loop is used:

from autoextract.aio import request_raw

async def foo():
    query = [{'url': 'http://example.com.foo', 'pageType': 'article'}]
    results1 = await request_raw(query)
    # ...

There is also request_parallel_as_completed function, which allows to process many URLs in parallel, using both batching and multiple connections:

import sys
from autoextract.aio import request_parallel_as_completed, create_session
from autoextract import ArticleRequest

async def extract_from(urls):
    requests = [ArticleRequest(url) for url in urls]
    async with create_session() as session:
        res_iter = request_parallel_as_completed(requests,
                                    n_conn=15, batch_size=2,
                                    session=session)
        for fut in res_iter:
            try:
                batch_result = await fut
                for res in batch_result:
                    # do something with a result, e.g.
                    print(json.dumps(res))
            except RequestError as e:
                print(e, file=sys.stderr)
                raise

request_parallel_as_completed is modelled after asyncio.as_completed (see https://docs.python.org/3/library/asyncio-task.html#asyncio.as_completed), and actually uses it under the hood.

Note from autoextract import ArticleRequest and its usage in the example above. There are several Request helper classes, which simplify building of the queries.

request_parallel_as_completed and request_raw functions handle throttling (http 429 errors) and network errors, retrying a request in these cases.

CLI interface implementation (autoextract/__main__.py) can serve as an usage example.

Request helpers

To query AutoExtract you need to create a dict with request parameters, e.g.:

{'url': 'http://example.com.foo', 'pageType': 'article'}

To simplify the library usage and avoid typos, scrapinghub-autpextract provides helper classes for constructing these dicts:

* autoextract.Request
* autoextract.ArticleRequest
* autoextract.ProductRequest
* autoextract.JobPostingRequest

You can pass instances of these classes instead of dicts everywhere when requests dicts are accepted. So e.g. instead of writing this:

query = [{"url": url, "pageType": "article"} for url in urls]

You can write this:

query = [Request(url, pageType="article") for url in urls]

or this:

query = [ArticleRequest(url) for url in urls]

There is one difference: articleBodyRaw parameter is set to false by default when Request or its variants are used, while it is true by default in the API.

0.3.0 (2020-07-24)

In this release retry-related features are added or improved. It is now possible to fix some of the temporary errors by enabling query-level retries, and the default retry behavior is improved.

• backwards-incompatible: autoextract.aio.ApiError is renamed to autoextract.aio.RequestError

• max_query_error_retries argument is added to autoextract.aio.request_raw and autoextract.aio.request_parallel_as_completed functions; it allows to enable retries of temporary query-level errors returned by the API.

• CLI: added --max-query-error-retries option to retry temporary query-level errors.

• HTTP 500 errors from server are retried now;

• documentation and test improvements.

0.2.0 (2020-04-15)

• asyncio API is rewritten, to simplify use in cases where passing meta is required. autoextract.aio.request_parallel_as_completed is added, autoextract.aio.request_parallel and autoextract.aio.request_batch are removed.

• CLI: it now shows various stats: mean response and connect time, % of throttling errors, % of network and other errors

• CLI: new --intype jl option allows to process a .jl file with arbitrary AutoExtract API queries

• CLI: new --shuffle option allows to shuffle input data, to spread it more evenly across websites.

• CLI: it no longer exits on unrecoverable errors, to aid long-running processing tasks.

• retry logic is adjusted to handle network errors better.

• autoextract.aio.request_raw and autoextract.aio.request_parallel_as_completed functions provide an interface to return statistics about requests made, including retries.

• autoextract.Request, autoextract.ArticleRequest, autoextract.ProductRequest, autoextract.JobPostingRequest helper classes

• Documentation improvements.

0.1.1 (2020-03-12)

• allow up to 100 elements in a batch, not up to 99

• custom User-Agent header is added

• Python 3.8 support is declared & tested

0.1 (2019-10-09)

Initial release.