zimmer

streaming/random access parser for the ZIM aka OpenZIM file format http://www.openzim.org/wiki/ZIM_file_format

requires the lzma-native native dependency for xz decompression (no pure js version available as of 2017)

$3

``js
var zimmer = require('zimmer')

zimmer.readHeader(fd, function (err, header) {})

var readable = zimmer.createOffsetStream(filename, start, num, opts)

var readable = zimmer.createClusterPointerStream(filename, header, opts)
var readable = zimmer.createEntryPointerStream(filename, header, opts)

zimmer.readDirectoryEntry(filename, fd, header, {index: 1}, function (err, entry) { })
zimmer.readCluster(filename, fd, header, {index: entry.cluster}, function (err, cluster) { })
`

$3

`
$ npm install zimmer -g

$ zimmer
zimmer zim parser - usage

zimmer - streams all entry metadata + data to stdout'
zimmer extract - extracts and writes files to output dir
zimmer header - reads zim header
zimmer entries - streams all entry metadata to stdout
zimmer entry - reads specific entry data by index
zimmer clusters - streams all cluster metadata to stdout
zimmer cluster - reads specific cluster data by index
`

examples

read a single entry's data by index:

`js
var filename = 'data.zim'
var index = 1

fs.open(filename, 'r', function (err, file) {
if (err) throw err
zim.readHeader(file, function(err, header) {
if (err) throw err
zim.readDirectoryEntry(filename, file, header, {index: index}, function (err, entry) {
if (err) throw err
zim.readCluster(filename, file, header, {index: entry.cluster}, function (err, cluster) {
if (err) throw err
var contents = cluster.blobs[entry.blob]
// contents is a buffer
})
})
})
})
`

read all entry data as a stream and pipe as ndjson to stdout

`js
var pump = require('pump')
var ndjson = require('ndjson')
var filename = 'data.zim'

fs.open(filename, 'r', function (err, file) {
if (err) throw err
zim.readHeader(file, function(err, header) {
if (err) throw err
var pointers = zim.createEntryPointerStream(filename, header)
var reader = through.obj(function(entry, enc, cb) {
zim.readDirectoryEntry(filename, file, header, entry, function (err, entry) {
if (err) throw err
if (!entry.cluster) return cb(null, {entry: entry})
zim.readCluster(filename, file, header, {index: entry.cluster}, function (err, cluster) {
if (err) return cb(err)
cb(null, {entry: entry, blob: cluster.blobs[entry.blob].toString()})
})
})
})
pump(pointers, reader, ndjson.serialize(), process.stdout, function (err) {
if (err) throw err
})
})
})
``