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urlmatching based compression algorithm

This project implements the URL compression algorithm descibed in the article "Scalable URL Matching with Small Memory Footprint" by Anat Bremler-Barr, David Hay, Daniel Krauthgamer and Shimrit Tzur David / IFIP Networking 2016 Conference. The algorithm was implemented by Daniel Krauthgamer.

  • The project should be compiled under C++11 or later
  • The project contains a tester code to test the performance of module.
  • The recommended parameters are n=1000,r=0.5,k=3 and n=1000,r=0.5,k=2 when running in LPM using . delimiter
  • To lean how to use the code explore the teseter's code in tester.cpp


URL matching lies at the core of many networking applications and Information Centric Networking architectures. For example, URL matching is extensively used by Layer 7 switches, ICN/NDN routers, load balancers, and security devices. Modern URL matching is done by maintaining a rich database that consists of tens of millions of URL which are classified to dozens of categories (or egress ports). In real-time, any input URL has to be searched in this database to find the corresponding category. In this paper, we introduce a generic framework for accurate URL matching (namely, no false positives or miscategorization) that aims to reduce the overall memory footprint, while still having low matching latency. We introduce a dictionary-based compression method that compresses the database by 60%, while having only a slight overhead in time. Our framework is very flexible and it allows hot-updates, cloud-based deployments, and can deal with strings that are not URLs.



The main module is located in UrlMatchingModule.h and contains api for:

  • Initialize / Store / Load the compression dicionary:
    • InitFromUrlsList
    • StoreDictToFileStream and StoreDictToFile
    • InitFromDictFileStream and InitFromDictFile
    • OptimizedACMachineSize - This is called from init methods when optimize_size=true It is needed since the original Compressed Aho-Corasick code has a non-efficient memory footprint only after it loads itself from a file
  • Encode / Decode
    • encode
    • decode

FileCompressor.h is module for archiving. Compress and store URL text file to disk, similar to zip

How to run the tester

UrlMatchingTester -f <file with urls from>

  • to explore all runtime options see urlmatching -h

      Usage: UrlMatchingTester [CMD] [-f urls_path] <options> <compression params>
       1. testing CMD: test, ,testhash, article
          -f [String] urls filepath  - required
          -o [String] ouput filepath		, default: None 
          -a          add header to output_filepath	, default: None 
          -p [String] Print dictionary file path	, default: None
          -v          Verify by Decode - longer	, default: no
          -b [Int]    Take break time to measure program memory, Seconds, default: no
          -u [String] custom urls for lookup in testhash , default: use the original urls file
       2. Building dictionary and encoding input file using existing dictionary 
          CMD: build, encode
          All of the above flags and:
          -d [String] dicionary filepath	, default: "[urlsfile].dict" 
          -x 0 To skip Offline stage, this yelp wrong compression ratio, default: 1 
       3. compress file CMD: compress, extract -f [input file] -o [output file] <compression params> 
       Compression params: 
          -l [char]    Longest Prefix Match - split dictionary by /, default: false
          -k [Int]     k-gram size			, default: 3
          -r [Fload]   consecutive k-gram ratio	, default: 0.5
          -n [Int]     number of pattern anchors	, default: 100
       Debugging flags:
          -s          dump Aho Corasik state machine	, default: No
          -c [String] logger config file		, default: None 
          -h prints this message

Repeating the tests in the article

  • Test files with urls are provided in test_files/
  • The source of full_domains file a tar file from
  • Extract all the urls using in scripts/
  • Some of the files are to big for github so they are in 7z container
  • The URLs file that used in the article is test_files/full_domains_shuffled
  • The scripts used to produce the graphs and data in the article are in scripts/, they might need to be updated with the executable name in order to use them.

How to build





Loggin flags

src/logger.h controls how debug prints are handled, simply configure the following code. Repository default is all set to NONE



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