| # yauzl |
| |
| [](https://travis-ci.org/thejoshwolfe/yauzl) |
| [](https://coveralls.io/r/thejoshwolfe/yauzl) |
| |
| yet another unzip library for node. For zipping, see |
| [yazl](https://github.com/thejoshwolfe/yazl). |
| |
| Design principles: |
| |
| * Follow the spec. |
| Don't scan for local file headers. |
| Read the central directory for file metadata. |
| (see [No Streaming Unzip API](#no-streaming-unzip-api)). |
| * Don't block the JavaScript thread. |
| Use and provide async APIs. |
| * Keep memory usage under control. |
| Don't attempt to buffer entire files in RAM at once. |
| * Never crash (if used properly). |
| Don't let malformed zip files bring down client applications who are trying to catch errors. |
| * Catch unsafe file names. |
| See `validateFileName()`. |
| |
| ## Usage |
| |
| ```js |
| var yauzl = require("yauzl"); |
| |
| yauzl.open("path/to/file.zip", {lazyEntries: true}, function(err, zipfile) { |
| if (err) throw err; |
| zipfile.readEntry(); |
| zipfile.on("entry", function(entry) { |
| if (/\/$/.test(entry.fileName)) { |
| // Directory file names end with '/'. |
| // Note that entires for directories themselves are optional. |
| // An entry's fileName implicitly requires its parent directories to exist. |
| zipfile.readEntry(); |
| } else { |
| // file entry |
| zipfile.openReadStream(entry, function(err, readStream) { |
| if (err) throw err; |
| readStream.on("end", function() { |
| zipfile.readEntry(); |
| }); |
| readStream.pipe(somewhere); |
| }); |
| } |
| }); |
| }); |
| ``` |
| |
| See also `examples/` for more usage examples. |
| |
| ## API |
| |
| The default for every optional `callback` parameter is: |
| |
| ```js |
| function defaultCallback(err) { |
| if (err) throw err; |
| } |
| ``` |
| |
| ### open(path, [options], [callback]) |
| |
| Calls `fs.open(path, "r")` and reads the `fd` effectively the same as `fromFd()` would. |
| |
| `options` may be omitted or `null`. The defaults are `{autoClose: true, lazyEntries: false, decodeStrings: true, validateEntrySizes: true, strictFileNames: false}`. |
| |
| `autoClose` is effectively equivalent to: |
| |
| ```js |
| zipfile.once("end", function() { |
| zipfile.close(); |
| }); |
| ``` |
| |
| `lazyEntries` indicates that entries should be read only when `readEntry()` is called. |
| If `lazyEntries` is `false`, `entry` events will be emitted as fast as possible to allow `pipe()`ing |
| file data from all entries in parallel. |
| This is not recommended, as it can lead to out of control memory usage for zip files with many entries. |
| See [issue #22](https://github.com/thejoshwolfe/yauzl/issues/22). |
| If `lazyEntries` is `true`, an `entry` or `end` event will be emitted in response to each call to `readEntry()`. |
| This allows processing of one entry at a time, and will keep memory usage under control for zip files with many entries. |
| |
| `decodeStrings` is the default and causes yauzl to decode strings with `CP437` or `UTF-8` as required by the spec. |
| The exact effects of turning this option off are: |
| |
| * `zipfile.comment`, `entry.fileName`, and `entry.fileComment` will be `Buffer` objects instead of `String`s. |
| * Any Info-ZIP Unicode Path Extra Field will be ignored. See `extraFields`. |
| * Automatic file name validation will not be performed. See `validateFileName()`. |
| |
| `validateEntrySizes` is the default and ensures that an entry's reported uncompressed size matches its actual uncompressed size. |
| This check happens as early as possible, which is either before emitting each `"entry"` event (for entries with no compression), |
| or during the `readStream` piping after calling `openReadStream()`. |
| See `openReadStream()` for more information on defending against zip bomb attacks. |
| |
| When `strictFileNames` is `false` (the default) and `decodeStrings` is `true`, |
| all backslash (`\`) characters in each `entry.fileName` are replaced with forward slashes (`/`). |
| The spec forbids file names with backslashes, |
| but Microsoft's `System.IO.Compression.ZipFile` class in .NET versions 4.5.0 until 4.6.1 |
| creates non-conformant zipfiles with backslashes in file names. |
| `strictFileNames` is `false` by default so that clients can read these |
| non-conformant zipfiles without knowing about this Microsoft-specific bug. |
| When `strictFileNames` is `true` and `decodeStrings` is `true`, |
| entries with backslashes in their file names will result in an error. See `validateFileName()`. |
| When `decodeStrings` is `false`, `strictFileNames` has no effect. |
| |
| The `callback` is given the arguments `(err, zipfile)`. |
| An `err` is provided if the End of Central Directory Record cannot be found, or if its metadata appears malformed. |
| This kind of error usually indicates that this is not a zip file. |
| Otherwise, `zipfile` is an instance of `ZipFile`. |
| |
| ### fromFd(fd, [options], [callback]) |
| |
| Reads from the fd, which is presumed to be an open .zip file. |
| Note that random access is required by the zip file specification, |
| so the fd cannot be an open socket or any other fd that does not support random access. |
| |
| `options` may be omitted or `null`. The defaults are `{autoClose: false, lazyEntries: false, decodeStrings: true, validateEntrySizes: true, strictFileNames: false}`. |
| |
| See `open()` for the meaning of the options and callback. |
| |
| ### fromBuffer(buffer, [options], [callback]) |
| |
| Like `fromFd()`, but reads from a RAM buffer instead of an open file. |
| `buffer` is a `Buffer`. |
| |
| If a `ZipFile` is acquired from this method, |
| it will never emit the `close` event, |
| and calling `close()` is not necessary. |
| |
| `options` may be omitted or `null`. The defaults are `{lazyEntries: false, decodeStrings: true, validateEntrySizes: true, strictFileNames: false}`. |
| |
| See `open()` for the meaning of the options and callback. |
| The `autoClose` option is ignored for this method. |
| |
| ### fromRandomAccessReader(reader, totalSize, [options], [callback]) |
| |
| This method of reading a zip file allows clients to implement their own back-end file system. |
| For example, a client might translate read calls into network requests. |
| |
| The `reader` parameter must be of a type that is a subclass of |
| [RandomAccessReader](#class-randomaccessreader) that implements the required methods. |
| The `totalSize` is a Number and indicates the total file size of the zip file. |
| |
| `options` may be omitted or `null`. The defaults are `{autoClose: true, lazyEntries: false, decodeStrings: true, validateEntrySizes: true, strictFileNames: false}`. |
| |
| See `open()` for the meaning of the options and callback. |
| |
| ### dosDateTimeToDate(date, time) |
| |
| Converts MS-DOS `date` and `time` data into a JavaScript `Date` object. |
| Each parameter is a `Number` treated as an unsigned 16-bit integer. |
| Note that this format does not support timezones, |
| so the returned object will use the local timezone. |
| |
| ### validateFileName(fileName) |
| |
| Returns `null` or a `String` error message depending on the validity of `fileName`. |
| If `fileName` starts with `"/"` or `/[A-Za-z]:\//` or if it contains `".."` path segments or `"\\"`, |
| this function returns an error message appropriate for use like this: |
| |
| ```js |
| var errorMessage = yauzl.validateFileName(fileName); |
| if (errorMessage != null) throw new Error(errorMessage); |
| ``` |
| |
| This function is automatically run for each entry, as long as `decodeStrings` is `true`. |
| See `open()`, `strictFileNames`, and `Event: "entry"` for more information. |
| |
| ### Class: ZipFile |
| |
| The constructor for the class is not part of the public API. |
| Use `open()`, `fromFd()`, `fromBuffer()`, or `fromRandomAccessReader()` instead. |
| |
| #### Event: "entry" |
| |
| Callback gets `(entry)`, which is an `Entry`. |
| See `open()` and `readEntry()` for when this event is emitted. |
| |
| If `decodeStrings` is `true`, entries emitted via this event have already passed file name validation. |
| See `validateFileName()` and `open()` for more information. |
| |
| If `validateEntrySizes` is `true` and this entry's `compressionMethod` is `0` (stored without compression), |
| this entry has already passed entry size validation. |
| See `open()` for more information. |
| |
| #### Event: "end" |
| |
| Emitted after the last `entry` event has been emitted. |
| See `open()` and `readEntry()` for more info on when this event is emitted. |
| |
| #### Event: "close" |
| |
| Emitted after the fd is actually closed. |
| This is after calling `close()` (or after the `end` event when `autoClose` is `true`), |
| and after all stream pipelines created from `openReadStream()` have finished reading data from the fd. |
| |
| If this `ZipFile` was acquired from `fromRandomAccessReader()`, |
| the "fd" in the previous paragraph refers to the `RandomAccessReader` implemented by the client. |
| |
| If this `ZipFile` was acquired from `fromBuffer()`, this event is never emitted. |
| |
| #### Event: "error" |
| |
| Emitted in the case of errors with reading the zip file. |
| (Note that other errors can be emitted from the streams created from `openReadStream()` as well.) |
| After this event has been emitted, no further `entry`, `end`, or `error` events will be emitted, |
| but the `close` event may still be emitted. |
| |
| #### readEntry() |
| |
| Causes this `ZipFile` to emit an `entry` or `end` event (or an `error` event). |
| This method must only be called when this `ZipFile` was created with the `lazyEntries` option set to `true` (see `open()`). |
| When this `ZipFile` was created with the `lazyEntries` option set to `true`, |
| `entry` and `end` events are only ever emitted in response to this method call. |
| |
| The event that is emitted in response to this method will not be emitted until after this method has returned, |
| so it is safe to call this method before attaching event listeners. |
| |
| After calling this method, calling this method again before the response event has been emitted will cause undefined behavior. |
| Calling this method after the `end` event has been emitted will cause undefined behavior. |
| Calling this method after calling `close()` will cause undefined behavior. |
| |
| #### openReadStream(entry, [options], callback) |
| |
| `entry` must be an `Entry` object from this `ZipFile`. |
| `callback` gets `(err, readStream)`, where `readStream` is a `Readable Stream` that provides the file data for this entry. |
| If this zipfile is already closed (see `close()`), the `callback` will receive an `err`. |
| |
| `options` may be omitted or `null`, and has the following defaults: |
| |
| ```js |
| { |
| decompress: entry.isCompressed() ? true : null, |
| decrypt: null, |
| start: 0, // actually the default is null, see below |
| end: entry.compressedSize, // actually the default is null, see below |
| } |
| ``` |
| |
| If the entry is compressed (with a supported compression method), |
| and the `decompress` option is `true` (or omitted), |
| the read stream provides the decompressed data. |
| Omitting the `decompress` option is what most clients should do. |
| |
| The `decompress` option must be `null` (or omitted) when the entry is not compressed (see `isCompressed()`), |
| and either `true` (or omitted) or `false` when the entry is compressed. |
| Specifying `decompress: false` for a compressed entry causes the read stream |
| to provide the raw compressed file data without going through a zlib inflate transform. |
| |
| If the entry is encrypted (see `isEncrypted()`), clients may want to avoid calling `openReadStream()` on the entry entirely. |
| Alternatively, clients may call `openReadStream()` for encrypted entries and specify `decrypt: false`. |
| If the entry is also compressed, clients must *also* specify `decompress: false`. |
| Specifying `decrypt: false` for an encrypted entry causes the read stream to provide the raw, still-encrypted file data. |
| (This data includes the 12-byte header described in the spec.) |
| |
| The `decrypt` option must be `null` (or omitted) for non-encrypted entries, and `false` for encrypted entries. |
| Omitting the `decrypt` option (or specifying it as `null`) for an encrypted entry |
| will result in the `callback` receiving an `err`. |
| This default behavior is so that clients not accounting for encrypted files aren't surprised by bogus file data. |
| |
| The `start` (inclusive) and `end` (exclusive) options are byte offsets into this entry's file data, |
| and can be used to obtain part of an entry's file data rather than the whole thing. |
| If either of these options are specified and non-`null`, |
| then the above options must be used to obain the file's raw data. |
| Speficying `{start: 0, end: entry.compressedSize}` will result in the complete file, |
| which is effectively the default values for these options, |
| but note that unlike omitting the options, when you specify `start` or `end` as any non-`null` value, |
| the above requirement is still enforced that you must also pass the appropriate options to get the file's raw data. |
| |
| It's possible for the `readStream` provided to the `callback` to emit errors for several reasons. |
| For example, if zlib cannot decompress the data, the zlib error will be emitted from the `readStream`. |
| Two more error cases (when `validateEntrySizes` is `true`) are if the decompressed data has too many |
| or too few actual bytes compared to the reported byte count from the entry's `uncompressedSize` field. |
| yauzl notices this false information and emits an error from the `readStream` |
| after some number of bytes have already been piped through the stream. |
| |
| This check allows clients to trust the `uncompressedSize` field in `Entry` objects. |
| Guarding against [zip bomb](http://en.wikipedia.org/wiki/Zip_bomb) attacks can be accomplished by |
| doing some heuristic checks on the size metadata and then watching out for the above errors. |
| Such heuristics are outside the scope of this library, |
| but enforcing the `uncompressedSize` is implemented here as a security feature. |
| |
| It is possible to destroy the `readStream` before it has piped all of its data. |
| To do this, call `readStream.destroy()`. |
| You must `unpipe()` the `readStream` from any destination before calling `readStream.destroy()`. |
| If this zipfile was created using `fromRandomAccessReader()`, the `RandomAccessReader` implementation |
| must provide readable streams that implement a `.destroy()` method (see `randomAccessReader._readStreamForRange()`) |
| in order for calls to `readStream.destroy()` to work in this context. |
| |
| #### close() |
| |
| Causes all future calls to `openReadStream()` to fail, |
| and closes the fd, if any, after all streams created by `openReadStream()` have emitted their `end` events. |
| |
| If the `autoClose` option is set to `true` (see `open()`), |
| this function will be called automatically effectively in response to this object's `end` event. |
| |
| If the `lazyEntries` option is set to `false` (see `open()`) and this object's `end` event has not been emitted yet, |
| this function causes undefined behavior. |
| If the `lazyEntries` option is set to `true`, |
| you can call this function instead of calling `readEntry()` to abort reading the entries of a zipfile. |
| |
| It is safe to call this function multiple times; after the first call, successive calls have no effect. |
| This includes situations where the `autoClose` option effectively calls this function for you. |
| |
| If `close()` is never called, then the zipfile is "kept open". |
| For zipfiles created with `fromFd()`, this will leave the `fd` open, which may be desirable. |
| For zipfiles created with `open()`, this will leave the underlying `fd` open, thereby "leaking" it, which is probably undesirable. |
| For zipfiles created with `fromRandomAccessReader()`, the reader's `close()` method will never be called. |
| For zipfiles created with `fromBuffer()`, the `close()` function has no effect whether called or not. |
| |
| Regardless of how this `ZipFile` was created, there are no resources other than those listed above that require cleanup from this function. |
| This means it may be desirable to never call `close()` in some usecases. |
| |
| #### isOpen |
| |
| `Boolean`. `true` until `close()` is called; then it's `false`. |
| |
| #### entryCount |
| |
| `Number`. Total number of central directory records. |
| |
| #### comment |
| |
| `String`. Always decoded with `CP437` per the spec. |
| |
| If `decodeStrings` is `false` (see `open()`), this field is the undecoded `Buffer` instead of a decoded `String`. |
| |
| ### Class: Entry |
| |
| Objects of this class represent Central Directory Records. |
| Refer to the zipfile specification for more details about these fields. |
| |
| These fields are of type `Number`: |
| |
| * `versionMadeBy` |
| * `versionNeededToExtract` |
| * `generalPurposeBitFlag` |
| * `compressionMethod` |
| * `lastModFileTime` (MS-DOS format, see `getLastModDateTime`) |
| * `lastModFileDate` (MS-DOS format, see `getLastModDateTime`) |
| * `crc32` |
| * `compressedSize` |
| * `uncompressedSize` |
| * `fileNameLength` (bytes) |
| * `extraFieldLength` (bytes) |
| * `fileCommentLength` (bytes) |
| * `internalFileAttributes` |
| * `externalFileAttributes` |
| * `relativeOffsetOfLocalHeader` |
| |
| #### fileName |
| |
| `String`. |
| Following the spec, the bytes for the file name are decoded with |
| `UTF-8` if `generalPurposeBitFlag & 0x800`, otherwise with `CP437`. |
| Alternatively, this field may be populated from the Info-ZIP Unicode Path Extra Field |
| (see `extraFields`). |
| |
| This field is automatically validated by `validateFileName()` before yauzl emits an "entry" event. |
| If this field would contain unsafe characters, yauzl emits an error instead of an entry. |
| |
| If `decodeStrings` is `false` (see `open()`), this field is the undecoded `Buffer` instead of a decoded `String`. |
| Therefore, `generalPurposeBitFlag` and any Info-ZIP Unicode Path Extra Field are ignored. |
| Furthermore, no automatic file name validation is performed for this file name. |
| |
| #### extraFields |
| |
| `Array` with each entry in the form `{id: id, data: data}`, |
| where `id` is a `Number` and `data` is a `Buffer`. |
| |
| This library looks for and reads the ZIP64 Extended Information Extra Field (0x0001) |
| in order to support ZIP64 format zip files. |
| |
| This library also looks for and reads the Info-ZIP Unicode Path Extra Field (0x7075) |
| in order to support some zipfiles that use it instead of General Purpose Bit 11 |
| to convey `UTF-8` file names. |
| When the field is identified and verified to be reliable (see the zipfile spec), |
| the the file name in this field is stored in the `fileName` property, |
| and the file name in the central directory record for this entry is ignored. |
| Note that when `decodeStrings` is false, all Info-ZIP Unicode Path Extra Fields are ignored. |
| |
| None of the other fields are considered significant by this library. |
| Fields that this library reads are left unalterned in the `extraFields` array. |
| |
| #### fileComment |
| |
| `String` decoded with the charset indicated by `generalPurposeBitFlag & 0x800` as with the `fileName`. |
| (The Info-ZIP Unicode Path Extra Field has no effect on the charset used for this field.) |
| |
| If `decodeStrings` is `false` (see `open()`), this field is the undecoded `Buffer` instead of a decoded `String`. |
| |
| Prior to yauzl version 2.7.0, this field was erroneously documented as `comment` instead of `fileComment`. |
| For compatibility with any code that uses the field name `comment`, |
| yauzl creates an alias field named `comment` which is identical to `fileComment`. |
| |
| #### getLastModDate() |
| |
| Effectively implemented as: |
| |
| ```js |
| return dosDateTimeToDate(this.lastModFileDate, this.lastModFileTime); |
| ``` |
| |
| #### isEncrypted() |
| |
| Returns is this entry encrypted with "Traditional Encryption". |
| Effectively implemented as: |
| |
| ```js |
| return (this.generalPurposeBitFlag & 0x1) !== 0; |
| ``` |
| |
| See `openReadStream()` for the implications of this value. |
| |
| Note that "Strong Encryption" is not supported, and will result in an `"error"` event emitted from the `ZipFile`. |
| |
| #### isCompressed() |
| |
| Effectively implemented as: |
| |
| ```js |
| return this.compressionMethod === 8; |
| ``` |
| |
| See `openReadStream()` for the implications of this value. |
| |
| ### Class: RandomAccessReader |
| |
| This class is meant to be subclassed by clients and instantiated for the `fromRandomAccessReader()` function. |
| |
| An example implementation can be found in `test/test.js`. |
| |
| #### randomAccessReader._readStreamForRange(start, end) |
| |
| Subclasses *must* implement this method. |
| |
| `start` and `end` are Numbers and indicate byte offsets from the start of the file. |
| `end` is exclusive, so `_readStreamForRange(0x1000, 0x2000)` would indicate to read `0x1000` bytes. |
| `end - start` will always be at least `1`. |
| |
| This method should return a readable stream which will be `pipe()`ed into another stream. |
| It is expected that the readable stream will provide data in several chunks if necessary. |
| If the readable stream provides too many or too few bytes, an error will be emitted. |
| (Note that `validateEntrySizes` has no effect on this check, |
| because this is a low-level API that should behave correctly regardless of the contents of the file.) |
| Any errors emitted on the readable stream will be handled and re-emitted on the client-visible stream |
| (returned from `zipfile.openReadStream()`) or provided as the `err` argument to the appropriate callback |
| (for example, for `fromRandomAccessReader()`). |
| |
| The returned stream *must* implement a method `.destroy()` |
| if you call `readStream.destroy()` on streams you get from `openReadStream()`. |
| If you never call `readStream.destroy()`, then streams returned from this method do not need to implement a method `.destroy()`. |
| `.destroy()` should abort any streaming that is in progress and clean up any associated resources. |
| `.destroy()` will only be called after the stream has been `unpipe()`d from its destination. |
| |
| Note that the stream returned from this method might not be the same object that is provided by `openReadStream()`. |
| The stream returned from this method might be `pipe()`d through one or more filter streams (for example, a zlib inflate stream). |
| |
| #### randomAccessReader.read(buffer, offset, length, position, callback) |
| |
| Subclasses may implement this method. |
| The default implementation uses `createReadStream()` to fill the `buffer`. |
| |
| This method should behave like `fs.read()`. |
| |
| #### randomAccessReader.close(callback) |
| |
| Subclasses may implement this method. |
| The default implementation is effectively `setImmediate(callback);`. |
| |
| `callback` takes parameters `(err)`. |
| |
| This method is called once the all streams returned from `_readStreamForRange()` have ended, |
| and no more `_readStreamForRange()` or `read()` requests will be issued to this object. |
| |
| ## How to Avoid Crashing |
| |
| When a malformed zipfile is encountered, the default behavior is to crash (throw an exception). |
| If you want to handle errors more gracefully than this, |
| be sure to do the following: |
| |
| * Provide `callback` parameters where they are allowed, and check the `err` parameter. |
| * Attach a listener for the `error` event on any `ZipFile` object you get from `open()`, `fromFd()`, `fromBuffer()`, or `fromRandomAccessReader()`. |
| * Attach a listener for the `error` event on any stream you get from `openReadStream()`. |
| |
| Minor version updates to yauzl will not add any additional requirements to this list. |
| |
| ## Limitations |
| |
| ### No Streaming Unzip API |
| |
| Due to the design of the .zip file format, it's impossible to interpret a .zip file from start to finish |
| (such as from a readable stream) without sacrificing correctness. |
| The Central Directory, which is the authority on the contents of the .zip file, is at the end of a .zip file, not the beginning. |
| A streaming API would need to either buffer the entire .zip file to get to the Central Directory before interpreting anything |
| (defeating the purpose of a streaming interface), or rely on the Local File Headers which are interspersed through the .zip file. |
| However, the Local File Headers are explicitly denounced in the spec as being unreliable copies of the Central Directory, |
| so trusting them would be a violation of the spec. |
| |
| Any library that offers a streaming unzip API must make one of the above two compromises, |
| which makes the library either dishonest or nonconformant (usually the latter). |
| This library insists on correctness and adherence to the spec, and so does not offer a streaming API. |
| |
| Here is a way to create a spec-conformant .zip file using the `zip` command line program (Info-ZIP) |
| available in most unix-like environments, that is (nearly) impossible to parse correctly with a streaming parser: |
| |
| ``` |
| $ echo -ne '\x50\x4b\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' > file.txt |
| $ zip -q0 - file.txt | cat > out.zip |
| ``` |
| |
| This .zip file contains a single file entry that uses General Purpose Bit 3, |
| which means the Local File Header doesn't know the size of the file. |
| Any streaming parser that encounters this situation will either immediately fail, |
| or attempt to search for the Data Descriptor after the file's contents. |
| The file's contents is a sequence of 16-bytes crafted to exactly mimic a valid Data Descriptor for an empty file, |
| which will fool any parser that gets this far into thinking that the file is empty rather than containing 16-bytes. |
| What follows the file's real contents is the file's real Data Descriptor, |
| which will likely cause some kind of signature mismatch error for a streaming parser (if one hasn't occurred already). |
| |
| By using General Purpose Bit 3 (and compression method 0), |
| it's possible to create arbitrarily ambiguous .zip files that |
| distract parsers with file contents that contain apparently valid .zip file metadata. |
| |
| ### Limitted ZIP64 Support |
| |
| For ZIP64, only zip files smaller than `8PiB` are supported, |
| not the full `16EiB` range that a 64-bit integer should be able to index. |
| This is due to the JavaScript Number type being an IEEE 754 double precision float. |
| |
| The Node.js `fs` module probably has this same limitation. |
| |
| ### ZIP64 Extensible Data Sector Is Ignored |
| |
| The spec does not allow zip file creators to put arbitrary data here, |
| but rather reserves its use for PKWARE and mentions something about Z390. |
| This doesn't seem useful to expose in this library, so it is ignored. |
| |
| ### No Multi-Disk Archive Support |
| |
| This library does not support multi-disk zip files. |
| The multi-disk fields in the zipfile spec were intended for a zip file to span multiple floppy disks, |
| which probably never happens now. |
| If the "number of this disk" field in the End of Central Directory Record is not `0`, |
| the `open()`, `fromFd()`, `fromBuffer()`, or `fromRandomAccessReader()` `callback` will receive an `err`. |
| By extension the following zip file fields are ignored by this library and not provided to clients: |
| |
| * Disk where central directory starts |
| * Number of central directory records on this disk |
| * Disk number where file starts |
| |
| ### Limited Encryption Handling |
| |
| You can detect when a file entry is encrypted with "Traditional Encryption" via `isEncrypted()`, |
| but yauzl will not help you decrypt it. |
| See `openReadStream()`. |
| |
| If a zip file contains file entries encrypted with "Strong Encryption", yauzl emits an error. |
| |
| If the central directory is encrypted or compressed, yauzl emits an error. |
| |
| ### Local File Headers Are Ignored |
| |
| Many unzip libraries mistakenly read the Local File Header data in zip files. |
| This data is officially defined to be redundant with the Central Directory information, |
| and is not to be trusted. |
| Aside from checking the signature, yauzl ignores the content of the Local File Header. |
| |
| ### No CRC-32 Checking |
| |
| This library provides the `crc32` field of `Entry` objects read from the Central Directory. |
| However, this field is not used for anything in this library. |
| |
| ### versionNeededToExtract Is Ignored |
| |
| The field `versionNeededToExtract` is ignored, |
| because this library doesn't support the complete zip file spec at any version, |
| |
| ### No Support For Obscure Compression Methods |
| |
| Regarding the `compressionMethod` field of `Entry` objects, |
| only method `0` (stored with no compression) |
| and method `8` (deflated) are supported. |
| Any of the other 15 official methods will cause the `openReadStream()` `callback` to receive an `err`. |
| |
| ### Data Descriptors Are Ignored |
| |
| There may or may not be Data Descriptor sections in a zip file. |
| This library provides no support for finding or interpreting them. |
| |
| ### Archive Extra Data Record Is Ignored |
| |
| There may or may not be an Archive Extra Data Record section in a zip file. |
| This library provides no support for finding or interpreting it. |
| |
| ### No Language Encoding Flag Support |
| |
| Zip files officially support charset encodings other than CP437 and UTF-8, |
| but the zip file spec does not specify how it works. |
| This library makes no attempt to interpret the Language Encoding Flag. |
| |
| ## Change History |
| |
| * 2.10.0 |
| * Added support for non-conformant zipfiles created by Microsoft, and added option `strictFileNames` to disable the workaround. [issue #66](https://github.com/thejoshwolfe/yauzl/issues/66), [issue #88](https://github.com/thejoshwolfe/yauzl/issues/88) |
| * 2.9.2 |
| * Removed `tools/hexdump-zip.js` and `tools/hex2bin.js`. Those tools are now located here: [thejoshwolfe/hexdump-zip](https://github.com/thejoshwolfe/hexdump-zip) and [thejoshwolfe/hex2bin](https://github.com/thejoshwolfe/hex2bin) |
| * Worked around performance problem with zlib when using `fromBuffer()` and `readStream.destroy()` for large compressed files. [issue #87](https://github.com/thejoshwolfe/yauzl/issues/87) |
| * 2.9.1 |
| * Removed `console.log()` accidentally introduced in 2.9.0. [issue #64](https://github.com/thejoshwolfe/yauzl/issues/64) |
| * 2.9.0 |
| * Throw an exception if `readEntry()` is called without `lazyEntries:true`. Previously this caused undefined behavior. [issue #63](https://github.com/thejoshwolfe/yauzl/issues/63) |
| * 2.8.0 |
| * Added option `validateEntrySizes`. [issue #53](https://github.com/thejoshwolfe/yauzl/issues/53) |
| * Added `examples/promises.js` |
| * Added ability to read raw file data via `decompress` and `decrypt` options. [issue #11](https://github.com/thejoshwolfe/yauzl/issues/11), [issue #38](https://github.com/thejoshwolfe/yauzl/issues/38), [pull #39](https://github.com/thejoshwolfe/yauzl/pull/39) |
| * Added `start` and `end` options to `openReadStream()`. [issue #38](https://github.com/thejoshwolfe/yauzl/issues/38) |
| * 2.7.0 |
| * Added option `decodeStrings`. [issue #42](https://github.com/thejoshwolfe/yauzl/issues/42) |
| * Fixed documentation for `entry.fileComment` and added compatibility alias. [issue #47](https://github.com/thejoshwolfe/yauzl/issues/47) |
| * 2.6.0 |
| * Support Info-ZIP Unicode Path Extra Field, used by WinRAR for Chinese file names. [issue #33](https://github.com/thejoshwolfe/yauzl/issues/33) |
| * 2.5.0 |
| * Ignore malformed Extra Field that is common in Android .apk files. [issue #31](https://github.com/thejoshwolfe/yauzl/issues/31) |
| * 2.4.3 |
| * Fix crash when parsing malformed Extra Field buffers. [issue #31](https://github.com/thejoshwolfe/yauzl/issues/31) |
| * 2.4.2 |
| * Remove .npmignore and .travis.yml from npm package. |
| * 2.4.1 |
| * Fix error handling. |
| * 2.4.0 |
| * Add ZIP64 support. [issue #6](https://github.com/thejoshwolfe/yauzl/issues/6) |
| * Add `lazyEntries` option. [issue #22](https://github.com/thejoshwolfe/yauzl/issues/22) |
| * Add `readStream.destroy()` method. [issue #26](https://github.com/thejoshwolfe/yauzl/issues/26) |
| * Add `fromRandomAccessReader()`. [issue #14](https://github.com/thejoshwolfe/yauzl/issues/14) |
| * Add `examples/unzip.js`. |
| * 2.3.1 |
| * Documentation updates. |
| * 2.3.0 |
| * Check that `uncompressedSize` is correct, or else emit an error. [issue #13](https://github.com/thejoshwolfe/yauzl/issues/13) |
| * 2.2.1 |
| * Update dependencies. |
| * 2.2.0 |
| * Update dependencies. |
| * 2.1.0 |
| * Remove dependency on `iconv`. |
| * 2.0.3 |
| * Fix crash when trying to read a 0-byte file. |
| * 2.0.2 |
| * Fix event behavior after errors. |
| * 2.0.1 |
| * Fix bug with using `iconv`. |
| * 2.0.0 |
| * Initial release. |