jsmediatags/build2/jsmediatags.js

Media Tags Reader (ID3, MP4)

'use strict';

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var MediaFileReader = require("./MediaFileReader");

var XhrFileReader = require("./XhrFileReader");

var BlobFileReader = require("./BlobFileReader");

var ArrayFileReader = require("./ArrayFileReader");

var MediaTagReader = require("./MediaTagReader");

var ID3v1TagReader = require("./ID3v1TagReader");

var ID3v2TagReader = require("./ID3v2TagReader");

var MP4TagReader = require("./MP4TagReader");

var FLACTagReader = require("./FLACTagReader");

var mediaFileReaders = [];
var mediaTagReaders = [];

function read(location, callbacks) {
  new Reader(location).read(callbacks);
}

function isRangeValid(range, fileSize) {
  var invalidPositiveRange = range.offset >= 0 && range.offset + range.length >= fileSize;
  var invalidNegativeRange = range.offset < 0 && (-range.offset > fileSize || range.offset + range.length > 0);
  return !(invalidPositiveRange || invalidNegativeRange);
}

var Reader = /*#__PURE__*/function () {
  function Reader(file) {
    _classCallCheck(this, Reader);

    _defineProperty(this, "_file", void 0);

    _defineProperty(this, "_tagsToRead", void 0);

    _defineProperty(this, "_fileReader", void 0);

    _defineProperty(this, "_tagReader", void 0);

    this._file = file;
  }

  _createClass(Reader, [{
    key: "setTagsToRead",
    value: function setTagsToRead(tagsToRead) {
      this._tagsToRead = tagsToRead;
      return this;
    }
  }, {
    key: "setFileReader",
    value: function setFileReader(fileReader) {
      this._fileReader = fileReader;
      return this;
    }
  }, {
    key: "setTagReader",
    value: function setTagReader(tagReader) {
      this._tagReader = tagReader;
      return this;
    }
  }, {
    key: "read",
    value: function read(callbacks) {
      var FileReader = this._getFileReader();

      var fileReader = new FileReader(this._file);
      var self = this;
      fileReader.init({
        onSuccess: function onSuccess() {
          self._getTagReader(fileReader, {
            onSuccess: function onSuccess(TagReader) {
              new TagReader(fileReader).setTagsToRead(self._tagsToRead).read(callbacks);
            },
            onError: callbacks.onError
          });
        },
        onError: callbacks.onError
      });
    }
  }, {
    key: "_getFileReader",
    value: function _getFileReader() {
      if (this._fileReader) {
        return this._fileReader;
      } else {
        return this._findFileReader();
      }
    }
  }, {
    key: "_findFileReader",
    value: function _findFileReader() {
      for (var i = 0; i < mediaFileReaders.length; i++) {
        if (mediaFileReaders[i].canReadFile(this._file)) {
          return mediaFileReaders[i];
        }
      }

      throw new Error("No suitable file reader found for " + this._file);
    }
  }, {
    key: "_getTagReader",
    value: function _getTagReader(fileReader, callbacks) {
      if (this._tagReader) {
        var tagReader = this._tagReader;
        setTimeout(function () {
          callbacks.onSuccess(tagReader);
        }, 1);
      } else {
        this._findTagReader(fileReader, callbacks);
      }
    }
  }, {
    key: "_findTagReader",
    value: function _findTagReader(fileReader, callbacks) {
      // We don't want to make multiple fetches per tag reader to get the tag
      // identifier. The strategy here is to combine all the tag identifier
      // ranges into one and make a single fetch. This is particularly important
      // in file readers that have expensive loads like the XHR one.
      // However, with this strategy we run into the problem of loading the
      // entire file because tag identifiers might be at the start or end of
      // the file.
      // To get around this we divide the tag readers into two categories, the
      // ones that read their tag identifiers from the start of the file and the
      // ones that read from the end of the file.
      var tagReadersAtFileStart = [];
      var tagReadersAtFileEnd = [];
      var fileSize = fileReader.getSize();

      for (var i = 0; i < mediaTagReaders.length; i++) {
        var range = mediaTagReaders[i].getTagIdentifierByteRange();

        if (!isRangeValid(range, fileSize)) {
          continue;
        }

        if (range.offset >= 0 && range.offset < fileSize / 2 || range.offset < 0 && range.offset < -fileSize / 2) {
          tagReadersAtFileStart.push(mediaTagReaders[i]);
        } else {
          tagReadersAtFileEnd.push(mediaTagReaders[i]);
        }
      }

      var tagsLoaded = false;
      var loadTagIdentifiersCallbacks = {
        onSuccess: function onSuccess() {
          if (!tagsLoaded) {
            // We're expecting to load two sets of tag identifiers. This flag
            // indicates when the first one has been loaded.
            tagsLoaded = true;
            return;
          }

          for (var i = 0; i < mediaTagReaders.length; i++) {
            var range = mediaTagReaders[i].getTagIdentifierByteRange();

            if (!isRangeValid(range, fileSize)) {
              continue;
            }

            try {
              var tagIndentifier = fileReader.getBytesAt(range.offset >= 0 ? range.offset : range.offset + fileSize, range.length);
            } catch (ex) {
              if (callbacks.onError) {
                callbacks.onError({
                  "type": "fileReader",
                  "info": ex.message
                });
              }

              return;
            }

            if (mediaTagReaders[i].canReadTagFormat(tagIndentifier)) {
              callbacks.onSuccess(mediaTagReaders[i]);
              return;
            }
          }

          if (callbacks.onError) {
            callbacks.onError({
              "type": "tagFormat",
              "info": "No suitable tag reader found"
            });
          }
        },
        onError: callbacks.onError
      };

      this._loadTagIdentifierRanges(fileReader, tagReadersAtFileStart, loadTagIdentifiersCallbacks);

      this._loadTagIdentifierRanges(fileReader, tagReadersAtFileEnd, loadTagIdentifiersCallbacks);
    }
  }, {
    key: "_loadTagIdentifierRanges",
    value: function _loadTagIdentifierRanges(fileReader, tagReaders, callbacks) {
      if (tagReaders.length === 0) {
        // Force async
        setTimeout(callbacks.onSuccess, 1);
        return;
      }

      var tagIdentifierRange = [Number.MAX_VALUE, 0];
      var fileSize = fileReader.getSize(); // Create a super set of all ranges so we can load them all at once.
      // Might need to rethink this approach if there are tag ranges too far
      // a part from each other. We're good for now though.

      for (var i = 0; i < tagReaders.length; i++) {
        var range = tagReaders[i].getTagIdentifierByteRange();
        var start = range.offset >= 0 ? range.offset : range.offset + fileSize;
        var end = start + range.length - 1;
        tagIdentifierRange[0] = Math.min(start, tagIdentifierRange[0]);
        tagIdentifierRange[1] = Math.max(end, tagIdentifierRange[1]);
      }

      fileReader.loadRange(tagIdentifierRange, callbacks);
    }
  }]);

  return Reader;
}();

var Config = /*#__PURE__*/function () {
  function Config() {
    _classCallCheck(this, Config);
  }

  _createClass(Config, null, [{
    key: "addFileReader",
    value: function addFileReader(fileReader) {
      mediaFileReaders.push(fileReader);
      return Config;
    }
  }, {
    key: "addTagReader",
    value: function addTagReader(tagReader) {
      mediaTagReaders.push(tagReader);
      return Config;
    }
  }, {
    key: "removeTagReader",
    value: function removeTagReader(tagReader) {
      var tagReaderIx = mediaTagReaders.indexOf(tagReader);

      if (tagReaderIx >= 0) {
        mediaTagReaders.splice(tagReaderIx, 1);
      }

      return Config;
    }
  }, {
    key: "EXPERIMENTAL_avoidHeadRequests",
    value: function EXPERIMENTAL_avoidHeadRequests() {
      XhrFileReader.setConfig({
        avoidHeadRequests: true
      });
    }
  }, {
    key: "setDisallowedXhrHeaders",
    value: function setDisallowedXhrHeaders(disallowedXhrHeaders) {
      XhrFileReader.setConfig({
        disallowedXhrHeaders: disallowedXhrHeaders
      });
    }
  }, {
    key: "setXhrTimeoutInSec",
    value: function setXhrTimeoutInSec(timeoutInSec) {
      XhrFileReader.setConfig({
        timeoutInSec: timeoutInSec
      });
    }
  }]);

  return Config;
}();

Config.addFileReader(XhrFileReader).addFileReader(BlobFileReader).addFileReader(ArrayFileReader).addTagReader(ID3v2TagReader).addTagReader(ID3v1TagReader).addTagReader(MP4TagReader).addTagReader(FLACTagReader);

if (typeof process !== "undefined" && !process.browser) {
  if (typeof navigator !== "undefined" && navigator.product === "ReactNative") {
    var ReactNativeFileReader = require('./ReactNativeFileReader');

    Config.addFileReader(ReactNativeFileReader);
  } else {
    var NodeFileReader = require('./NodeFileReader');

    Config.addFileReader(NodeFileReader);
  }
}

module.exports = {
  "read": read,
  "Reader": Reader,
  "Config": Config
};