Corpora

C++ application for fast search in multiple huge text corpora, using one Trie per corpus.

Offers a socket API in order to submit queries and get a response.

Corpus files are loaded in memory the first time they're required. If you load huge corpus files (more than 1 million elements) then the socket request may timeout before the file is entirely loaded. In this case two strategies:

• Extend timeout in client
• Make a dummy query at initialization of your app so corpora preloads files

Run

./corpora [-r root-path] [-p socket-port] [-h socket-host]

Options:

• -r [root-path] Root path of the corpus files
• -h [socket-host] Socket host
• -p [socket-port] Socket port
• -v Activate verbose mode (display various benchmarks)

Querying

To query the service, you have to send a list of corpuses you want to check (without the .txt extension), along with the word or expression to send, separated with a space.

For example, to search term Hello in corpus [root]/en/some_corpus.txt:

en/some_corpus Hello

Multiple corpus files query

If you need to search many corpus files, separate them with a comma ,:

en/some_corpus,en/other Hello

will try to load both [root]/en/some_corpus.txt and [root]/en/other.txt corpus files.

Error handling

Corpora gracefully handles errors, and trying to search an unexisting corpus won't block current or subsequent queries.

Responses

Response is formatted with a "header" that is the amount of corpus where the keyword was found, followed by the list of corpus files.

[length],[corpus_file],[other_corpus_file]

So sending en/some_corpus,en/other Hello may return:

• 0 if no result has been found
• 1,en/some_corpus if a result has been found in some_corpus file
• 2,en/some_corpus,en/other if a result has been found in both corpus files.

Dictionaries

Dictionary files must follow this strict:

[root]
    |
    |- [language]
    |   |
    |   |- [corpus-name].txt
    |   |- [corpus-name].txt
    |
    |- [language]
    |   |
    |   |- [corpus-name].txt
    |   |- [corpus-name].txt

Per convention, language folders are two code letters of the language: en, fr... and exceptionally 5 letters codes for specific languages subsets: zh-tw.

In dictionaries, you should have only one term or expression per line:

some
word
another
one
and
so
on

Build

The make command should work on most UNIX platforms:

make

Install tests

Tests relies on node.js and mocha. Install node and npm if you need to run tests.

cd test && npm install .

Run tests

# Start corpora with test dataset root
./corpora -r test/corpus/

# Then in another terminal, run test suite
cd test && mocha

Examples of use

Example of querying corpora using core Node.js net connections

var net = require("net"),
    socket;

// Create a socket connection
socket = net.createConnection(1234, "localhost", function (){

socket.on ('data', function (d){
    var res = d.toString();
    console.log(res);
    // 2,en/names,en/places
});

socket.write('en/words,en/names,en/places,en/companies paris');