nsIZipReader

Implemented by: @mozilla.org/libjar/zip-reader;1. To create an instance, use:

var zipReader = Components.classes["@mozilla.org/libjar/zip-reader;1"]
                .createInstance(Components.interfaces.nsIZipReader);

About character sets and code pages

Starting in Gecko 10.0 (Firefox 10.0 / Thunderbird 10.0 / SeaMonkey 2.7), the nsIZipReader API supports a limited 8 bit code page usage. All functions now pass the filenames (both in and out) as AUTF8String. So you can now read and extract  what you wrote with nsIZipWriter. If you show filenames from the findEntries() result in the user interface,  the character matching is only fine on UTF-8  ZIP archives.

Method overview

Attributes

Methods

close()

Closes a zip reader. Subsequent attempts to extract() files or read from its input stream will result in an error. Subsequent attempts to access a nsIZipEntry obtained from this zip reader will cause unspecified behavior.

void close();

Parameters

None.

extract()

Extracts a zip entry into a local file specified by outFile. The entry must be stored in the zip in either uncompressed or DEFLATE-compressed format for the extraction to be successful. If the entry is a directory, the directory will be extracted non-recursively.

void extract(
  in AUTF8String zipEntry,
  in nsIFile outFile
);

Parameters

zipEntry

The zip entry to extract.

outFile

The local file destination used to extract the zip entry.

Returns a string enumerator containing the matching entry names.

nsIUTF8StringEnumerator findEntries(
  in AUTF8String aPattern
);

Parameters

aPattern

A regular expression used to find matching entries in the zip file. Set this parameter to null (javascript) or EmptyCString() (c++) to get all entries; otherwise, use the following syntax:

• * matches anything.
• ? matches one character.
• $ matches the end of the string.
• [abc] matches one occurrence of a, b, or c. The only character that must be escaped inside the brackets is ]. ^ and - must never appear in the first and second positions within the brackets, respectively. (In the former case, the behavior specified for '[^az]' will happen.)
• [a-z] matches any character between a and z. The characters a and z must either both be letters or both be numbers, with the character represented by 'a' having a lower ASCII value than the character represented by 'z'.
• [^az] matches any character except a or z. If ] is to appear inside the brackets as a character to not match, it must be escaped.
• Pat~pat2 returns matches to the pattern 'pat' which do not also match the pattern 'pat2'. This may be used to perform filtering upon the results of one pattern to remove all matches which also match another pattern. For example, because '*' matches any string and '*z*' matches any string containing a 'z', '*~*z*' will match all strings except those containing a 'z'. Note that a pattern may not use '~' multiple times, so a string such as '*~*z*~*y*' is not a valid pattern.
• (foo|bar) will match either the pattern foo or the pattern bar. Neither of the patterns foo or bar may use the 'pat~pat2' syntax described immediately above.
• \ will escape a special character. Escaping is required for all special characters unless otherwise specified.
• All other characters match case-sensitively.

 

An aPattern not conforming to this syntax has undefined behavior.

Return value

The nsIUTF8StringEnumerator containing the matching entry names.

Exceptions thrown

NS_ERROR_ILLEGAL_VALUE

On many but not all invalid aPattern values.

Returns an object describing the entity which signed an entry. parseManifest must be called first. If aEntryName is an entry in the jar, getInputStream() must be called after parseManifest. If aEntryName is an external file which has meta-information stored in the jar, verifyExternalFile (not yet implemented) must be called before getPrincipal.

nsIPrincipal getCertificatePrincipal(
  in string aEntryName
);

Parameters

aEntryName

Missing Description

Return value

An nsIPrincipal.

getEntry()

Returns a nsIZipEntry describing a specified zip entry.

nsIZipEntry getEntry(
  in AUTF8String zipEntry
);

Parameters

zipEntry

The zip entry.

Return value

The nsIZipEntry for the given zip entry.

getInputStream()

Returns an input stream containing the contents of the specified zip entry.

nsIInputStream getInputStream(
  in AUTF8String zipEntry
);

Parameters

zipEntry

The name of the entry to open() the stream from.

Return value

The nsIInputStream containing the contents of the specified zip entry.

Returns an input stream containing the contents of the specified zip entry. If the entry refers to a directory (ends with '/'), a directory stream is opened, otherwise the contents of the file entry is returned.

nsIInputStream getInputStreamWithSpec(
  in AUTF8String aJarSpec,
  in AUTF8String zipEntry
);

Parameters

aJarSpec

The Spec of the URI for the JAR (only used for directory streams).

zipEntry

The name of the entry to open() the stream from.

Return value

The nsIInputStream containing the contents of the specified zip entry.

Checks whether the zipfile contains an entry specified by zipEntry.

boolean hasEntry(
  in AUTF8String zipEntry
);

Parameters

zipEntry

The zip entry.

Return value

Boolean value, true if the zip entry exists, false is it does not exist.

Initializes a zip reader after construction.

void init(
  in nsIFile zipFile
);

Parameters

zipFile

Zip file to initialize.

open()

Opens a zip file for reading. It is allowed to open with another file, but it needs to be closed first with close().

void open(
  in nsIFile zipFile 
);

Parameters

zipFile

The zip file to open.

Opens a zip file inside a zip file for reading.

void openInner(
  in nsIZipReader zipReader, 
  in AUTF8String zipEntry
);

Parameters

 

zipReader

The zipReader object.

zipEntry

The zip entry.

test()

Tests the integrity of the archive by performing a CRC check on each item expanded into memory. If an entry is specified the integrity of only that item is tested. If null (javascript) or EmptyCString() (c++) is passed in the integrity of all items in the archive are tested.

void test(
  in AUTF8String aEntryName
);

Parameters

aEntryName

The single entity to check or null for checking all entries in the archive.

Examples

List contents of XPI and read file contents

This example uses findEntries, getEntry, getInputStream, open, and close. It also uses nsIScriptableInputStream to read the stream returned by getInputStream. XPI files are ZIP files, just Firefox needs the extension to be XPI. Change "[email protected]" to the name of a XPI file in your extensions folder. Then you can copy and paste this code in scratchpad to run it.

    var zr = Cc["@mozilla.org/libjar/zip-reader;1"].createInstance(Ci.nsIZipReader);
    Cu.import('resource://gre/modules/osfile.jsm');
    Cu.import('resource://gre/modules/FileUtils.jsm');
    
    var reusableStreamInstance = Cc['@mozilla.org/scriptableinputstream;1'].createInstance(Ci.nsIScriptableInputStream);
    
    var pathToXpiToRead = OS.Path.join(OS.Constants.Path.profileDir, 'extensions', '[email protected]');
    var nsiFileXpi = new FileUtils.File(pathToXpiToRead);
    
    //Services.ww.activeWindow.alert(pathToXpiToRead);
    
    try {
      zr.open(nsiFileXpi); //if file dne it throws here
      var entries = zr.findEntries('*'); //we use asterik because we want EVERYTHING listed out
      while (entries.hasMore()) {
        var entryPointer = entries.getNext(); //just a string of "zip path" (this means path to file in zip, and it uses forward slashes remember)
        var entry = zr.getEntry(entryPointer); // should return true on `entry instanceof Ci.nsIZipEntry`
        console.log('entryPointer', entryPointer);
        /* CONSOLE OUTPUT
         * "entryPointer" "bootstrap.js" Scratchpad/1:18
         */
        console.info('entry', entry);
        /* CONSOLE OUTPUT
         * "entry" XPCWrappedNative_NoHelper { QueryInterface: QueryInterface(), compression: Getter, size: Getter, realSize: Getter, CRC32: Getter, isDirectory: Getter, lastModifiedTime: Getter, isSynthetic: Getter, permissions: Getter, compression: 8 } Scratchpad/1:19
         */
        if (!entry.isDirectory) {
            var inputStream = zr.getInputStream(entryPointer);
            reusableStreamInstance.init(inputStream);
            var fileContents = reusableStreamInstance.read(entry.realSize);
            console.log('contenst of file=', fileContents);
        } else {
            console.log('is directory, no stream to read');
        }
      }
    } catch (ex) {
      console.warn('exception occured = ', ex);
      if (ex.name == 'NS_ERROR_FILE_NOT_FOUND') {
        Services.ww.activeWindow.alert('XPI at path does not exist!\n\nPath = ' + pathToXpiToRead);
      }
    } finally {
      zr.close();
      console.log('zr closed');
    }

See also

• nsIZipEntry
• nsIZipWriter