mirror of
https://github.com/pocoproject/poco.git
synced 2024-12-28 03:51:39 +01:00
162 lines
7.4 KiB
Plaintext
162 lines
7.4 KiB
Plaintext
POCO Zip User Guide
|
|
POCO Zip Library
|
|
|
|
!!!Introduction
|
|
POCO Zip adds support for parsing and creating Zip files. It offers the following features:
|
|
* decompress from local files
|
|
* decompress from network files while they are downloaded
|
|
* compress to local files
|
|
* compress directly to a network destination
|
|
|
|
!!Restrictions
|
|
* POCO Zip does not support the DEFLATE64 algorithm.
|
|
* encrypted files are not supported
|
|
|
|
!!!Main Classes
|
|
Most users will work with two common classes: <*Compress*> and <*Decompress*>
|
|
|
|
!!Compress
|
|
Compress is a helper class that simplifies creation of Zip files.
|
|
Creating a Zip file is a basically a three-step process:
|
|
* Create the Compress object: Specify the output stream and define if it is seekable (set to true for local files, to false for network files)
|
|
|
|
Compress(std::ostream& out, bool seekableOut);
|
|
----
|
|
* Add entries: either add single files or directory entries
|
|
|
|
void addFile(std::istream& input,
|
|
const Poco::DateTime& lastModifiedAt,
|
|
const Poco::Path& fileName,
|
|
ZipCommon::CompressionMethod cm = ZipCommon::CM_DEFLATE,
|
|
ZipCommon::CompressionLevel cl = ZipCommon::CL_MAXIMUM);
|
|
/// Adds a single file to the Zip File. fileName must not be a directory name.
|
|
|
|
void addFile(const Poco::Path& file,
|
|
const Poco::Path& fileName,
|
|
ZipCommon::CompressionMethod cm = ZipCommon::CM_DEFLATE,
|
|
ZipCommon::CompressionLevel cl = ZipCommon::CL_MAXIMUM);
|
|
/// Adds a single file to the Zip File. fileName must not be a directory name. The file must exist physically!
|
|
|
|
void addDirectory(const Poco::Path& entryName, const Poco::DateTime& lastModifiedAt);
|
|
/// Adds a directory entry excluding all children to the Zip file, entryName must not be empty.
|
|
|
|
void addRecursive(const Poco::Path& entry,
|
|
ZipCommon::CompressionLevel cl = ZipCommon::CL_MAXIMUM,
|
|
bool excludeRoot = true,
|
|
const Poco::Path& name = Poco::Path());
|
|
/// Adds a directory entry recursively to the zip file, set excludeRoot to false to exclude the parent directory.
|
|
/// The name specifies under which path the entries are added in the Zip file.
|
|
----
|
|
Note that one must always define a name when adding a file entry, otherwise the compresser can not decide if the file should be added with an absolute or a relative path.
|
|
Assume you are adding the file <*c:\\data\\hello.txt*> twice to a Zip:
|
|
|
|
// MUST use binary!
|
|
std::ofstream out("test.zip", std::ios::binary);
|
|
Compress c(out, true);
|
|
Poco::Path aFile("c:\\data\\hello.txt");
|
|
c.addFile(theFile, "hello.txt");
|
|
c.addFile(theFile, theFile);
|
|
c.close(); // MUST be done to finalize the Zip file
|
|
----
|
|
A Zip file stores entries internally in UNIX path style. The Zip file created above will contain the following entries:
|
|
|
|
hello.txt
|
|
data/
|
|
data/hello.txt
|
|
----
|
|
The directory entry <*data/*> was automatically added.
|
|
|
|
When adding directories recursively, the same principle applies. You specify the root directory that should be added and an optional path name where entries are added in the Zip file.
|
|
Assume you have the following directory structure:
|
|
|
|
data/
|
|
run1/
|
|
result1.txt
|
|
run2/
|
|
result2.txt
|
|
----
|
|
The following call will add all subdirectories and all files of data to the Zip but not the root entry <*data*>:
|
|
|
|
Poco::Path data("data");
|
|
data.makeDirectory();
|
|
c.addRecursive(data);
|
|
----
|
|
Or if you want the files to be added under the directory name <*20070401*> (you basically <*rename*> data to 20070401):
|
|
|
|
Poco::Path data("data");
|
|
Poco::Path name("20070401);
|
|
data.makeDirectory();
|
|
name.makeDirectory();
|
|
c.addRecursive(data, ZipCommon::CL_NORMAL, false, name);
|
|
----
|
|
Note that <*makeDirectory*> does not create a directory, it simply assures that the Path is treated as a directory not as a file.
|
|
Also using NORMAL compression instead of MAXIMUM (which is the default) has the benefit of improved performance.
|
|
To get notified about the entries that are added during <*addRecursive*> register to the <!EDone!> event of the Compress object:
|
|
|
|
Poco::FIFOEvent<const ZipLocalFileHeader> EDone;
|
|
----
|
|
* Closing the Zip file: It is mandatory to manually close Compress objects. This guarantees that the Zip directory is written, thus creating a valid Zip file. It is safe to call <*close*> multiple times, only the first call takes effect.
|
|
|
|
ZipArchive close();
|
|
----
|
|
<*close*> returns a ZipArchive which describes all entries inside a Zip file.
|
|
|
|
!!Decompress
|
|
Decompress can be used to decompress all files from a Zip file or to decompress single files only.
|
|
|
|
!Decompress All
|
|
The following sample code shows how all entries can be extracted from a Zip file:
|
|
|
|
std::ifstream inp("test.zip", std::ios::binary);
|
|
poco_assert (inp);
|
|
// decompress to current working dir
|
|
Decompress dec(inp, Poco::Path());
|
|
// if an error happens invoke the ZipTest::onDecompressError method
|
|
dec.EError += Poco::Delegate<ZipTest, std::pair<const Poco::Zip::ZipLocalFileHeader, const std::string> >(this, &ZipTest::onDecompressError);
|
|
dec.decompressAllFiles();
|
|
dec.EError -= Poco::Delegate<ZipTest, std::pair<const Poco::Zip::ZipLocalFileHeader, const std::string> >(this, &ZipTest::onDecompressError);
|
|
----
|
|
The onDecompressError method:
|
|
|
|
void ZipTest::onDecompressError(const void* pSender, std::pair<const Poco::Zip::ZipLocalFileHeader, const std::string>& info)
|
|
{
|
|
// inform user about error
|
|
[...]
|
|
}
|
|
----
|
|
Decompressing directly from the net works similar:
|
|
|
|
Poco::URI uri("http://www.appinf.com/test.zip");
|
|
HTTPClientSession session(uri.getHost(), uri.getPort());
|
|
HTTPRequest req(HTTPRequest::HTTP_GET, path, HTTPMessage::HTTP_1_1);
|
|
session.sendRequest(req);
|
|
HTTPResponse res;
|
|
std::istream& rs = session.receiveResponse(res);
|
|
Decompress dec(rs, Poco::Path());
|
|
// if an error happens invoke the ZipTest::onDecompressError method
|
|
dec.EError += Poco::Delegate<ZipTest, std::pair<const Poco::Zip::ZipLocalFileHeader, const std::string> >(this, &ZipTest::onDecompressError);
|
|
dec.decompressAllFiles();
|
|
dec.EError -= Poco::Delegate<ZipTest, std::pair<const Poco::Zip::ZipLocalFileHeader, const std::string> >(this, &ZipTest::onDecompressError);
|
|
----
|
|
Furthermore, Decompress supports additional parameters:
|
|
|
|
Decompress(std::istream& in, const Poco::Path& outputDir, bool flattenDirs = false, bool keepIncompleteFiles = false);
|
|
----
|
|
If <*flattenDirs*> is set to true no subdirs are extracted, if <*keepIncompleteFiles*> is set to true, corrupt files (i.e. wrong CRC, wrong size on disk) will not be deleted.
|
|
|
|
!Decompress Single Files
|
|
To decompress single files you must first parse a Zip file, and then decompress the file which happens transparently inside the <*ZipInputStream*>:
|
|
|
|
std::ifstream inp("test.zip", std::ios::binary);
|
|
poco_assert (inp);
|
|
ZipArchive arch(inp);
|
|
ZipArchive::FileHeaders::const_iterator it = arch.findHeader("data/hello.txt");
|
|
poco_assert (it != arch.headerEnd());
|
|
ZipInputStream zipin (inp, it->second);
|
|
std::ostringstream out(std::ios::binary);
|
|
Poco::StreamCopier::copyStream(zipin, out);
|
|
----
|
|
Note that this will only work with local files which allow us to seek inside the file.
|
|
Directly extracting single entries from a network file is currently not possible via the Decompress class.
|
|
|