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https://github.com/scrapy/scurl

Performance-focused replacement for Python urllib
https://github.com/scrapy/scurl

chromium cython gurl python urlparse

Last synced: about 1 month ago
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Performance-focused replacement for Python urllib

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README 

        
# Scurl



[![Build Status](https://travis-ci.org/scrapy/scurl.svg?branch=master)](https://travis-ci.org/scrapy/scurl)

[![codecov](https://codecov.io/gh/scrapy/scurl/branch/master/graph/badge.svg)](https://codecov.io/gh/scrapy/scurl)



## About Scurl



Scurl is a library that is meant to replace some functions in `urllib`, such as `urlparse`,

`urlsplit` and `urljoin`. It is built using the Chromium url parse source, which is called GURL.



In addition, this library is built to support the Scrapy project (hence the name Scurl).

Therefore, an additional function is built, which is `canonicalize_url`, the bottleneck

function in Scrapy spiders. It uses the canonicalize function from GURL to canonicalize

the path, fragment and query of the urls.



Since the library is built based on Chromium source, the performance is greatly

increased. The performance of `urlparse`, `urlsplit` and `urljoin` is 2-3 times faster than

the urllib.



At the moment, we run the tests from `urllib` and `w3lib`. Nearly all the tests

from urllib have passed (we are still working on passing all the tests :) ).



## Credits



We want to give special thanks to [`urlparse4`](https://github.com/commonsearch/urlparse4)

since this project is built based on it.



## GSoC 2018



This project is built under the funding of the Google Summer of Code program 2018.

More detail about the program can be found [here](https://summerofcode.withgoogle.com/).



The final report, which contains more detail on how this project was made can be found

[here](https://gist.github.com/nctl144/48c924e039a612f009b7827768feb184).



## Supported functions



Since scurl meant to replace those functions in urllib, these are supported by Scurl:

`urlparse`, `urljoin`, `urlsplit` and `canonicalize_url`.



## Installation



Scurl has not been deployed to pypi yet. Currently the only way to install Scurl is

cloning this repository



```

git clone https://github.com/scrapy/scurl

cd scurl

pip install -r requirements.txt

make clean

make build_ext

make install

```



## Available `Make` commands



Make commands create a shorter way to type commands while developing :)



`make clean`



This will clean the build dir and the files that are generated when running `build_ext` command



`make test`



This will run all the tests found in the `/tests` folder



`make build_ext`



This will run the command `python setup.py build_ext --inplace`, which builds Cython code

for this project.



`make sdist`



This will run `python setup.py sdist` command on this project.



`make install`



This will run `python setup.py install` command on this project.



`make develop`



This will run `python setup.py develop` command on this project.



`make perf`



Run the performance tests on `urlparse`, `urlsplit` and `urljoin`.



`make cano`:



Run the performance tests on `canonicalize_url`.



## Profiling



Scurl repository has the built-in profiling tool, which you can turn on by adding this

lines to the top of the `*.pyx` files in `scurl/scurl`:



```

# cython: profile=True

```



Then you can run `python benchmarks/cython_profile.py --func [function-name]` to get the

cprofiling result. Currently, Scurl supports profiling `urlparse`, `urlsplit` and `canonicalize`.



This is not the most convenient way to profile Scurl with cprofiler, but we will come

up with a way of improving this soon!



## Benchmarking result report



### urlparse, urlsplit and urljoin

This shows the performance difference between `urlparse`, `urlsplit` and `urljoin` from

`urllib.parse` and those of `Scurl` (this is measured by running these functions with the

urls from the file `chromiumUrls.txt`, which can also be found in this project):



The `chromiumUrls.txt` file contains ~83k urls. This measure the time it takes to run the

`performance_test.py` test.



|               | urlparse      | urlsplit    | urljoin  |

| ------------- |:-------------:|:-----------:|:--------:|

| urllib.parse  | 0.52 sec      | 0.39 sec    | 1.33 sec |

| Scurl         | 0.19 sec      | 0.10 sec    | 0.17 sec |



### Canonicalize urls

The speed of `canonicalize_url` from [scrapy/w3lib](https://github.com/scrapy/w3lib)

compared to the speed of `canonicalize_url` from Scurl (this is measured by running

`canonicalize_url` with the urls from the file `chromiumUrls.txt`, which can also be

found in this project):



This measures the speed of both functions. The test can be found in `canonicalize_test.py`

file.



|               |canonicalize_url |

| ------------- |:---------------:|

| scrapy/w3lib  | 22,757 items/sec|

| Scurl         | 46,199 items/sec|



## Feedback



Any feedback is highly appreciated :) Please feel free to submit any

error/feedback in the repository issue tab!