How To Write A Batch File To Automatically Zip A Given Folder
Sometimes it can be useful to programmatically create zip archives or extract files from existing archives. Windows PowerShell 5.0 added two cmdlets for doing just that. The Compress-Archive cmdlet enables you to create new archives from folders or individual files and to add files to archives; Extract-Archive can be used to unzip files.
How To Write A Batch File To Automatically Zip A Given Folder
Note that I added the -Force parameter to overwrite the archive that I created using the first command. Without the -Force parameter, you cannot overwrite existing archives and PowerShell will prompt you to add files to the archive instead.
Extracting files from an archive is even easier than creating one. All you need to do is specify the name of the archive and the destination folder for the unzipped files. The command below extracts the contents of the Invoices.zip archive to a folder named InvoicesUnzipped using the Expand-Archive cmdlet.
Resources are, in fact, a special case. When a package is installed into a project, NuGet automatically adds assembly references to the package's DLLs, excluding those that are named .resources.dll because they are assumed to be localized satellite assemblies (see Creating localized packages). For this reason, avoid using .resources.dll for files that otherwise contain essential package code.
Because a NuGet package is just a ZIP file that's been renamed with the .nupkg extension, it's often easiest to create the folder structure you want on your local file system, then create the .nuspec file directly from that structure. The nuget pack command then automatically adds all files in that folder structure (excluding any folders that begin with ., allowing you to keep private files in the same structure).
The advantage to this approach is that you don't need to specify in the manifest which files you want to include in the package (as explained later in this topic). You can simply have your build process produce the exact folder structure that goes into the package, and you can easily include other files that might not be part of a project otherwise:
Again, the generated .nuspec contains no explicit references to files in the folder structure. NuGet automatically includes all files when the package is created. You still need to edit placeholder values in other parts of the manifest, however.
Creating a .nuspec from a .csproj or .vbproj file is convenient because other packages that have been installed into those project are automatically referenced as dependencies. Simply use the following command in the same folder as the project file:
NuGet 2.x supported the notion of a solution-level package that installs tools or additional commands for the Package Manager Console (the contents of the tools folder), but does not add references, content, or build customizations to any projects in the solution. Such packages contain no files in its direct lib, content, or build folders, and none of its dependencies have files in their respective lib, content, or build folders.
You can use various command-line switches with nuget pack to exclude files, override the version number in the manifest, and change the output folder, among other features. For a complete list, refer to the pack command reference.
PKWARE is the company that created and first implemented this file format. The company put together and maintains the current format specification, which is publicly available and allows the creation of products, programs, and processes that read and write files using the ZIP file format.
ZIP files are everywhere. For example, office suites such as Microsoft Office and Libre Office rely on the ZIP file format as their document container file. This means that .docx, .xlsx, .pptx, .odt, .ods, .odp files are actually ZIP archives containing several files and folders that make up each document. Other common files that use the ZIP format include .jar, .war, and .epub files.
Knowing how to create, read, write, and extract ZIP files can be a useful skill for developers and professionals who work with computers and digital information. Among other benefits, ZIP files allow you to:
To get your working environment ready, place the downloaded resources into a directory called python-zipfile/ in your home folder. Once you have the files in the right place, move to the newly created directory and fire up a Python interactive session there.
Now say you want to add hello.txt to a hello.zip archive using ZipFile. To do that, you can use the write mode ("w"). This mode opens a ZIP file for writing. If the target ZIP file exists, then the "w" mode truncates it and writes any new content you pass in.
You can also use .open() with the "w" mode. This mode allows you to create a new member file, write content to it, and finally append the file to the underlying archive, which you should open in append mode:
In the first code snippet, you open sample.zip in append mode ("a"). Then you create new_hello.txt by calling .open() with the "w" mode. This function returns a file-like object that supports .write(), which allows you to write bytes into the newly created file.
In this example, you write b'Hello, World!' into new_hello.txt. When the execution flow exits the inner with statement, Python writes the input bytes to the member file. When the outer with statement exits, Python writes new_hello.txt to the underlying ZIP file, sample.zip.
The second code snippet confirms that new_hello.txt is now a member file of sample.zip. A detail to notice in the output of this example is that .write() sets the Modified date of the newly added file to 1980-01-01 00:00:00, which is a weird behavior that you should keep in mind when using this method.
As you learned in the above section, you can use the .read() and .write() methods to read from and write to member files without extracting them from the containing ZIP archive. Both of these methods work exclusively with bytes.
Because ZipFile.read() returns the content of the target member file as bytes, .decode() can operate on these bytes directly. The .decode() method decodes a bytes object into a string using a given character encoding format.
ZipFile.extract() allows you to accomplish the first task. This method takes the name of a member file and extracts it to a given directory signaled by path. The destination path defaults to the current directory:
After running this code, all the current content of sample.zip will be in your output_dir/ directory. If you pass a non-existing directory to .extractall(), then this method automatically creates the directory. Finally, if any of the member files already exist in the destination directory, then .extractall() will overwrite them without asking for your confirmation, so be careful.
If you only need to extract some of the member files from a given archive, then you can use the members argument. This argument accepts a list of member files, which should be a subset of the whole list of files in the archive at hand. Finally, just like .extract(), the .extractall() method also accepts a pwd argument to extract encrypted files.
The call to .close() closes archive for you. You must call .close() before exiting your program. Otherwise, some writing operations might not be executed. For example, if you open a ZIP file for appending ("a") new member files, then you need to close the archive to write the files.
Sometimes you need to create a ZIP archive from several related files. This way, you can have all the files in a single container for distributing them over a computer network or sharing them with friends or colleagues. To this end, you can create a list of target files and write them into an archive using ZipFile and a loop:
The for loop iterates over your list of input files and writes them into the underlying ZIP file using .write(). Once the execution flow exits the with statement, ZipFile automatically closes the archive, saving the changes for you. Now you have a multiple_files.zip archive containing all the files from your original list of files.
Bundling the content of a directory into a single archive is another everyday use case for ZIP files. Python has several tools that you can use with zipfile to approach this task. For example, you can use pathlib to read the content of a given directory. With that information, you can create a container archive using ZipFile.
This time, you use Path.relative_to() to get the relative path to each file and then pass the result to the second argument of .write(). This way, the resulting ZIP file ends up with the same internal structure as your original source directory. Again, you can get rid of this argument if you want your source directory to be at the root of your ZIP file.
The compression method is the third argument to the initializer of ZipFile. If you want to compress your files while you write them into a ZIP archive, then you can set this argument to one of the following constants:
This code shows that zipfile.Path implements several features that are common to a pathlib.Path object. You can get the name of the file with .name. You can check if the path points to a regular file with .is_file(). You can check if a given file exists inside a particular ZIP file, and more.
PyZipFile provides the same interface as ZipFile, with the addition of .writepy(). This method can take a Python file (.py) as an argument and add it to the underlying ZIP file. If optimize is -1 (the default), then the .py file is automatically compiled to a .pyc file and then added to the target archive. Why does this happen?
The call to .writepy() takes the hello package as an argument, searches for .py files inside it, compiles them to .pyc files, and finally adds them to the target ZIP file, hello.zip. Again, you can import your code from this archive by following the steps that you learned before:
The command in the previous instructions allows you to delete files in a folder older than 30 days, but you need to open Command Prompt and execute the command manually whenever you want to free up space.