Access the Github V3 api and find all watchers for a specified user's repositories. Generates output suitable for processing by https://gist.github.com/2475460

repos.groovy

@Grab('org.codehaus.groovy.modules.http-builder:http-builder:0.5.2')
import groovy.json.JsonBuilder
import groovyx.net.http.HTTPBuilder
import static groovyx.net.http.ContentType.JSON

final rootUser = args[0]
final String RATE_LIMIT_HEADER = 'X-RateLimit-Remaining'
final String rootUrl = 'https://api.github.com'
final Closure<Boolean> hasWatchers = {it.watchers > 1}
final Closure findReposForUser = { HTTPBuilder http, username ->
    http.get(path: "/users/$username/repos", contentType: JSON) { resp, json ->
        return [resp.headers[RATE_LIMIT_HEADER].value as int, json.toList()]
    }
}
final Closure findWatchers = { HTTPBuilder http, username, repo ->
    http.get(path: "/repos/$username/$repo/watchers", contentType: JSON) { resp, json ->
        return [resp.headers[RATE_LIMIT_HEADER].value as int, json.toList()*.login.flatten().unique() - username]
    }
}

LinkedList nodes = [rootUser] as LinkedList
Map<String, List> usersToRepos = [:]
Map<String, List<String>> watcherMap = [:]
boolean hasRemainingCalls = true
final HTTPBuilder builder = new HTTPBuilder(rootUrl)
//add a default error handler
builder.handler.failure = { resp ->
    "Unexpected failure: ${resp.statusLine}"
}
while(!nodes.isEmpty() && hasRemainingCalls)
{
    String username = nodes.remove()
    println "processing $username"
    println "remaining nodes = ${nodes.size()}"

    def remainingApiCalls, repos, watchers
    (remainingApiCalls, repos) = findReposForUser(builder, username)
    usersToRepos[username] = repos
    hasRemainingCalls = remainingApiCalls > 300
    repos.findAll(hasWatchers).each{ repo ->
        (remainingApiCalls, watchers) =  findWatchers(builder, username, repo.name)
        def oldValue = watcherMap.get(username, [] as LinkedHashSet)
        oldValue.addAll(watchers)
        watcherMap[username] =  oldValue
        nodes.addAll(watchers)
        nodes.removeAll(watcherMap.keySet())
        hasRemainingCalls = remainingApiCalls > 300
    }
    if(!hasRemainingCalls)
    {
        println "Stopped with $remainingApiCalls api calls left."
        println "Still have not processed ${nodes.size()} users."
    }
}

new File('reposOutput.json').withWriter {writer ->
    writer << new JsonBuilder(watcherMap).toPrettyString()
}

As per the Github REST API v3 Watching docs:

In August 2012, we changed the way watching works on GitHub. At the time of that change, many API clients were already using the existing "watcher" endpoints to access starring data. To avoid breaking those applications, the legacy "watcher" endpoints continue to provide starring data.

This script is now consuming the starring data instead of watchers on the repo. Add the subscribers endpoint here: path: "/repos/$username/$repo/subscribers" to get users watching the repo.