Category Archives: Create Your Own Tools

Finding the Versions of All Java Jars in a Directory

Tasked with converting a project to Maven, I needed to find out the version of the dependencies, as not all of them had the version in the name.

jars-without-versions-edited

Looking Up a Single Jar

If it’s a single jar you want to look up, it’s quite easy.  Simply take the sha1 hash of the file, head over to the Maven Central Advanced Search, and put the hash in the “SHA-1 Checksum” field.

maven-central-search-results

Looking Up Many Jars

The above becomes very tedious very quick if you have dozens of jars to lookup.  A whole directory of mysterious dependencies.

Maven Central has a search API that I quickly took advantage of to automate the above process in Python.  I created a script that will, for every file in a given path, hash the file and search for its version.

You simply run it as >jar_version.py <path>

jar-versions-found

The Script

Feel free to use the script.

import sys
import urllib2
import json
import os


def sha1_of_file(file_path):
    import hashlib
    with open(file_path, 'rb') as f:
        return hashlib.sha1(f.read()).hexdigest()


def search_maven_central(sha1_hash):
    maven_hash_url = "http://search.maven.org/solrsearch/select?q=1:%22" + sha1_hash + "%22&rows=20&wt=json"
    response = urllib2.urlopen(maven_hash_url)
    return response.read()


def pull_result_version_from_results(maven_central_response):
    results_parsed = json.loads(maven_central_response)
    if results_parsed["response"]["numFound"] == 0:
        return "Not Found"
    else:
        specific_results = results_parsed["response"]["docs"][0]
        return specific_results["g"] + " " + specific_results["a"] + " v" + specific_results["v"]


def process_artifact(artifact_path):
    sha1_hash = sha1_of_file(artifact_path)
    html = search_maven_central(sha1_hash)
    result_value = pull_result_version_from_results(html)
    print artifact_path + " -> " + result_value


def main():
    path = sys.argv[1]
    if os.path.isfile(path):
        process_artifact(path)
    else:
        for root, _, files in os.walk(path):
            for f in files:
                full_path = os.path.join(root, f)
                process_artifact(full_path)


main()