315 lines
12 KiB
JavaScript
315 lines
12 KiB
JavaScript
"use strict";
|
|
Object.defineProperty(exports, "__esModule", { value: true });
|
|
exports.GridFSBucketReadStream = void 0;
|
|
const stream_1 = require("stream");
|
|
const error_1 = require("../error");
|
|
/**
|
|
* A readable stream that enables you to read buffers from GridFS.
|
|
*
|
|
* Do not instantiate this class directly. Use `openDownloadStream()` instead.
|
|
* @public
|
|
*/
|
|
class GridFSBucketReadStream extends stream_1.Readable {
|
|
/** @internal
|
|
* @param chunks - Handle for chunks collection
|
|
* @param files - Handle for files collection
|
|
* @param readPreference - The read preference to use
|
|
* @param filter - The filter to use to find the file document
|
|
*/
|
|
constructor(chunks, files, readPreference, filter, options) {
|
|
super();
|
|
this.s = {
|
|
bytesToTrim: 0,
|
|
bytesToSkip: 0,
|
|
bytesRead: 0,
|
|
chunks,
|
|
expected: 0,
|
|
files,
|
|
filter,
|
|
init: false,
|
|
expectedEnd: 0,
|
|
options: {
|
|
start: 0,
|
|
end: 0,
|
|
...options
|
|
},
|
|
readPreference
|
|
};
|
|
}
|
|
/**
|
|
* Reads from the cursor and pushes to the stream.
|
|
* Private Impl, do not call directly
|
|
* @internal
|
|
*/
|
|
_read() {
|
|
if (this.destroyed)
|
|
return;
|
|
waitForFile(this, () => doRead(this));
|
|
}
|
|
/**
|
|
* Sets the 0-based offset in bytes to start streaming from. Throws
|
|
* an error if this stream has entered flowing mode
|
|
* (e.g. if you've already called `on('data')`)
|
|
*
|
|
* @param start - 0-based offset in bytes to start streaming from
|
|
*/
|
|
start(start = 0) {
|
|
throwIfInitialized(this);
|
|
this.s.options.start = start;
|
|
return this;
|
|
}
|
|
/**
|
|
* Sets the 0-based offset in bytes to start streaming from. Throws
|
|
* an error if this stream has entered flowing mode
|
|
* (e.g. if you've already called `on('data')`)
|
|
*
|
|
* @param end - Offset in bytes to stop reading at
|
|
*/
|
|
end(end = 0) {
|
|
throwIfInitialized(this);
|
|
this.s.options.end = end;
|
|
return this;
|
|
}
|
|
/**
|
|
* Marks this stream as aborted (will never push another `data` event)
|
|
* and kills the underlying cursor. Will emit the 'end' event, and then
|
|
* the 'close' event once the cursor is successfully killed.
|
|
*
|
|
* @param callback - called when the cursor is successfully closed or an error occurred.
|
|
*/
|
|
abort(callback) {
|
|
this.push(null);
|
|
this.destroyed = true;
|
|
if (this.s.cursor) {
|
|
this.s.cursor.close(error => {
|
|
this.emit(GridFSBucketReadStream.CLOSE);
|
|
callback && callback(error);
|
|
});
|
|
}
|
|
else {
|
|
if (!this.s.init) {
|
|
// If not initialized, fire close event because we will never
|
|
// get a cursor
|
|
this.emit(GridFSBucketReadStream.CLOSE);
|
|
}
|
|
callback && callback();
|
|
}
|
|
}
|
|
}
|
|
exports.GridFSBucketReadStream = GridFSBucketReadStream;
|
|
/**
|
|
* An error occurred
|
|
* @event
|
|
*/
|
|
GridFSBucketReadStream.ERROR = 'error';
|
|
/**
|
|
* Fires when the stream loaded the file document corresponding to the provided id.
|
|
* @event
|
|
*/
|
|
GridFSBucketReadStream.FILE = 'file';
|
|
/**
|
|
* Emitted when a chunk of data is available to be consumed.
|
|
* @event
|
|
*/
|
|
GridFSBucketReadStream.DATA = 'data';
|
|
/**
|
|
* Fired when the stream is exhausted (no more data events).
|
|
* @event
|
|
*/
|
|
GridFSBucketReadStream.END = 'end';
|
|
/**
|
|
* Fired when the stream is exhausted and the underlying cursor is killed
|
|
* @event
|
|
*/
|
|
GridFSBucketReadStream.CLOSE = 'close';
|
|
function throwIfInitialized(stream) {
|
|
if (stream.s.init) {
|
|
throw new error_1.MongoGridFSStreamError('Options cannot be changed after the stream is initialized');
|
|
}
|
|
}
|
|
function doRead(stream) {
|
|
if (stream.destroyed)
|
|
return;
|
|
if (!stream.s.cursor)
|
|
return;
|
|
if (!stream.s.file)
|
|
return;
|
|
stream.s.cursor.next((error, doc) => {
|
|
if (stream.destroyed) {
|
|
return;
|
|
}
|
|
if (error) {
|
|
stream.emit(GridFSBucketReadStream.ERROR, error);
|
|
return;
|
|
}
|
|
if (!doc) {
|
|
stream.push(null);
|
|
process.nextTick(() => {
|
|
if (!stream.s.cursor)
|
|
return;
|
|
stream.s.cursor.close(error => {
|
|
if (error) {
|
|
stream.emit(GridFSBucketReadStream.ERROR, error);
|
|
return;
|
|
}
|
|
stream.emit(GridFSBucketReadStream.CLOSE);
|
|
});
|
|
});
|
|
return;
|
|
}
|
|
if (!stream.s.file)
|
|
return;
|
|
const bytesRemaining = stream.s.file.length - stream.s.bytesRead;
|
|
const expectedN = stream.s.expected++;
|
|
const expectedLength = Math.min(stream.s.file.chunkSize, bytesRemaining);
|
|
if (doc.n > expectedN) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, new error_1.MongoGridFSChunkError(`ChunkIsMissing: Got unexpected n: ${doc.n}, expected: ${expectedN}`));
|
|
}
|
|
if (doc.n < expectedN) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, new error_1.MongoGridFSChunkError(`ExtraChunk: Got unexpected n: ${doc.n}, expected: ${expectedN}`));
|
|
}
|
|
let buf = Buffer.isBuffer(doc.data) ? doc.data : doc.data.buffer;
|
|
if (buf.byteLength !== expectedLength) {
|
|
if (bytesRemaining <= 0) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, new error_1.MongoGridFSChunkError(`ExtraChunk: Got unexpected n: ${doc.n}, expected file length ${stream.s.file.length} bytes but already read ${stream.s.bytesRead} bytes`));
|
|
}
|
|
return stream.emit(GridFSBucketReadStream.ERROR, new error_1.MongoGridFSChunkError(`ChunkIsWrongSize: Got unexpected length: ${buf.byteLength}, expected: ${expectedLength}`));
|
|
}
|
|
stream.s.bytesRead += buf.byteLength;
|
|
if (buf.byteLength === 0) {
|
|
return stream.push(null);
|
|
}
|
|
let sliceStart = null;
|
|
let sliceEnd = null;
|
|
if (stream.s.bytesToSkip != null) {
|
|
sliceStart = stream.s.bytesToSkip;
|
|
stream.s.bytesToSkip = 0;
|
|
}
|
|
const atEndOfStream = expectedN === stream.s.expectedEnd - 1;
|
|
const bytesLeftToRead = stream.s.options.end - stream.s.bytesToSkip;
|
|
if (atEndOfStream && stream.s.bytesToTrim != null) {
|
|
sliceEnd = stream.s.file.chunkSize - stream.s.bytesToTrim;
|
|
}
|
|
else if (stream.s.options.end && bytesLeftToRead < doc.data.byteLength) {
|
|
sliceEnd = bytesLeftToRead;
|
|
}
|
|
if (sliceStart != null || sliceEnd != null) {
|
|
buf = buf.slice(sliceStart || 0, sliceEnd || buf.byteLength);
|
|
}
|
|
stream.push(buf);
|
|
});
|
|
}
|
|
function init(stream) {
|
|
const findOneOptions = {};
|
|
if (stream.s.readPreference) {
|
|
findOneOptions.readPreference = stream.s.readPreference;
|
|
}
|
|
if (stream.s.options && stream.s.options.sort) {
|
|
findOneOptions.sort = stream.s.options.sort;
|
|
}
|
|
if (stream.s.options && stream.s.options.skip) {
|
|
findOneOptions.skip = stream.s.options.skip;
|
|
}
|
|
stream.s.files.findOne(stream.s.filter, findOneOptions, (error, doc) => {
|
|
if (error) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, error);
|
|
}
|
|
if (!doc) {
|
|
const identifier = stream.s.filter._id
|
|
? stream.s.filter._id.toString()
|
|
: stream.s.filter.filename;
|
|
const errmsg = `FileNotFound: file ${identifier} was not found`;
|
|
// TODO(NODE-3483)
|
|
const err = new error_1.MongoRuntimeError(errmsg);
|
|
err.code = 'ENOENT'; // TODO: NODE-3338 set property as part of constructor
|
|
return stream.emit(GridFSBucketReadStream.ERROR, err);
|
|
}
|
|
// If document is empty, kill the stream immediately and don't
|
|
// execute any reads
|
|
if (doc.length <= 0) {
|
|
stream.push(null);
|
|
return;
|
|
}
|
|
if (stream.destroyed) {
|
|
// If user destroys the stream before we have a cursor, wait
|
|
// until the query is done to say we're 'closed' because we can't
|
|
// cancel a query.
|
|
stream.emit(GridFSBucketReadStream.CLOSE);
|
|
return;
|
|
}
|
|
try {
|
|
stream.s.bytesToSkip = handleStartOption(stream, doc, stream.s.options);
|
|
}
|
|
catch (error) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, error);
|
|
}
|
|
const filter = { files_id: doc._id };
|
|
// Currently (MongoDB 3.4.4) skip function does not support the index,
|
|
// it needs to retrieve all the documents first and then skip them. (CS-25811)
|
|
// As work around we use $gte on the "n" field.
|
|
if (stream.s.options && stream.s.options.start != null) {
|
|
const skip = Math.floor(stream.s.options.start / doc.chunkSize);
|
|
if (skip > 0) {
|
|
filter['n'] = { $gte: skip };
|
|
}
|
|
}
|
|
stream.s.cursor = stream.s.chunks.find(filter).sort({ n: 1 });
|
|
if (stream.s.readPreference) {
|
|
stream.s.cursor.withReadPreference(stream.s.readPreference);
|
|
}
|
|
stream.s.expectedEnd = Math.ceil(doc.length / doc.chunkSize);
|
|
stream.s.file = doc;
|
|
try {
|
|
stream.s.bytesToTrim = handleEndOption(stream, doc, stream.s.cursor, stream.s.options);
|
|
}
|
|
catch (error) {
|
|
return stream.emit(GridFSBucketReadStream.ERROR, error);
|
|
}
|
|
stream.emit(GridFSBucketReadStream.FILE, doc);
|
|
});
|
|
}
|
|
function waitForFile(stream, callback) {
|
|
if (stream.s.file) {
|
|
return callback();
|
|
}
|
|
if (!stream.s.init) {
|
|
init(stream);
|
|
stream.s.init = true;
|
|
}
|
|
stream.once('file', () => {
|
|
callback();
|
|
});
|
|
}
|
|
function handleStartOption(stream, doc, options) {
|
|
if (options && options.start != null) {
|
|
if (options.start > doc.length) {
|
|
throw new error_1.MongoInvalidArgumentError(`Stream start (${options.start}) must not be more than the length of the file (${doc.length})`);
|
|
}
|
|
if (options.start < 0) {
|
|
throw new error_1.MongoInvalidArgumentError(`Stream start (${options.start}) must not be negative`);
|
|
}
|
|
if (options.end != null && options.end < options.start) {
|
|
throw new error_1.MongoInvalidArgumentError(`Stream start (${options.start}) must not be greater than stream end (${options.end})`);
|
|
}
|
|
stream.s.bytesRead = Math.floor(options.start / doc.chunkSize) * doc.chunkSize;
|
|
stream.s.expected = Math.floor(options.start / doc.chunkSize);
|
|
return options.start - stream.s.bytesRead;
|
|
}
|
|
throw new error_1.MongoInvalidArgumentError('Start option must be defined');
|
|
}
|
|
function handleEndOption(stream, doc, cursor, options) {
|
|
if (options && options.end != null) {
|
|
if (options.end > doc.length) {
|
|
throw new error_1.MongoInvalidArgumentError(`Stream end (${options.end}) must not be more than the length of the file (${doc.length})`);
|
|
}
|
|
if (options.start == null || options.start < 0) {
|
|
throw new error_1.MongoInvalidArgumentError(`Stream end (${options.end}) must not be negative`);
|
|
}
|
|
const start = options.start != null ? Math.floor(options.start / doc.chunkSize) : 0;
|
|
cursor.limit(Math.ceil(options.end / doc.chunkSize) - start);
|
|
stream.s.expectedEnd = Math.ceil(options.end / doc.chunkSize);
|
|
return Math.ceil(options.end / doc.chunkSize) * doc.chunkSize - options.end;
|
|
}
|
|
throw new error_1.MongoInvalidArgumentError('End option must be defined');
|
|
}
|
|
//# sourceMappingURL=download.js.map
|