34.1. msilib — Read and write Microsoft Installer files

Source code: Lib/msilib/__init__.py

The msilib supports the creation of Microsoft Installer (.msi) files. Because these files often contain an embedded “cabinet” file (.cab), it also exposes an API to create CAB files. Support for reading .cab files is currently not implemented; read support for the .msi database is possible.

This package aims to provide complete access to all tables in an .msi file, therefore, it is a fairly low-level API. Two primary applications of this package are the distutils command bdist_msi, and the creation of Python installer package itself (although that currently uses a different version of msilib).

The package contents can be roughly split into four parts: low-level CAB routines, low-level MSI routines, higher-level MSI routines, and standard table structures.

msilib.FCICreate(cabname, files)

Create a new CAB file named cabname. files must be a list of tuples, each containing the name of the file on disk, and the name of the file inside the CAB file.

The files are added to the CAB file in the order they appear in the list. All files are added into a single CAB file, using the MSZIP compression algorithm.

Callbacks to Python for the various steps of MSI creation are currently not exposed.


Return the string representation of a new unique identifier. This wraps the Windows API functions UuidCreate() and UuidToString().

msilib.OpenDatabase(path, persist)

Return a new database object by calling MsiOpenDatabase. path is the file name of the MSI file; persist can be one of the constants MSIDBOPEN_CREATEDIRECT, MSIDBOPEN_CREATE, MSIDBOPEN_DIRECT, MSIDBOPEN_READONLY, or MSIDBOPEN_TRANSACT, and may include the flag MSIDBOPEN_PATCHFILE. See the Microsoft documentation for the meaning of these flags; depending on the flags, an existing database is opened, or a new one created.


Return a new record object by calling MSICreateRecord(). count is the number of fields of the record.

msilib.init_database(name, schema, ProductName, ProductCode, ProductVersion, Manufacturer)

Create and return a new database name, initialize it with schema, and set the properties ProductName, ProductCode, ProductVersion, and Manufacturer.

schema must be a module object containing tables and _Validation_records attributes; typically, msilib.schema should be used.

The database will contain just the schema and the validation records when this function returns.

msilib.add_data(database, table, records)

Add all records to the table named table in database.

The table argument must be one of the predefined tables in the MSI schema, e.g. 'Feature', 'File', 'Component', 'Dialog', 'Control', etc.

records should be a list of tuples, each one containing all fields of a record according to the schema of the table. For optional fields, None can be passed.

Field values can be ints, strings, or instances of the Binary class.

class msilib.Binary(filename)

Represents entries in the Binary table; inserting such an object using add_data() reads the file named filename into the table.

msilib.add_tables(database, module)

Add all table content from module to database. module must contain an attribute tables listing all tables for which content should be added, and one attribute per table that has the actual content.

This is typically used to install the sequence tables.

msilib.add_stream(database, name, path)

Add the file path into the _Stream table of database, with the stream name name.


Return a new UUID, in the format that MSI typically requires (i.e. in curly braces, and with all hexdigits in upper-case).

34.1.1. Database Objects


Return a view object, by calling MSIDatabaseOpenView(). sql is the SQL statement to execute.


Commit the changes pending in the current transaction, by calling MSIDatabaseCommit().


Return a new summary information object, by calling MsiGetSummaryInformation(). count is the maximum number of updated values.

34.1.2. View Objects


Execute the SQL query of the view, through MSIViewExecute(). If params is not None, it is a record describing actual values of the parameter tokens in the query.


Return a record describing the columns of the view, through calling MsiViewGetColumnInfo(). kind can be either MSICOLINFO_NAMES or MSICOLINFO_TYPES.


Return a result record of the query, through calling MsiViewFetch().

View.Modify(kind, data)


data must be a record describing the new data.


Close the view, through MsiViewClose().

34.1.3. Summary Information Objects




Return the number of summary properties, through MsiSummaryInfoGetPropertyCount().

SummaryInformation.SetProperty(field, value)

Set a property through MsiSummaryInfoSetProperty(). field can have the same values as in GetProperty(), value is the new value of the property. Possible value types are integer and string.


Write the modified properties to the summary information stream, using MsiSummaryInfoPersist().

34.1.4. Record Objects


Return the number of fields of the record, through MsiRecordGetFieldCount().


Return the value of field as an integer where possible. field must be an integer.


Return the value of field as a string where possible. field must be an integer.

Record.SetString(field, value)

Set field to value through MsiRecordSetString(). field must be an integer; value a string.

Record.SetStream(field, value)

Set field to the contents of the file named value, through MsiRecordSetStream(). field must be an integer; value a string.

Record.SetInteger(field, value)

Set field to value through MsiRecordSetInteger(). Both field and value must be an integer.


Set all fields of the record to 0, through MsiRecordClearData().

34.1.5. Errors

All wrappers around MSI functions raise MSIError; the string inside the exception will contain more detail.

34.1.6. CAB Objects

class msilib.CAB(name)

The class CAB represents a CAB file. During MSI construction, files will be added simultaneously to the Files table, and to a CAB file. Then, when all files have been added, the CAB file can be written, then added to the MSI file.

name is the name of the CAB file in the MSI file.

append(full, file, logical)

Add the file with the pathname full to the CAB file, under the name logical. If there is already a file named logical, a new file name is created.

Return the index of the file in the CAB file, and the new name of the file inside the CAB file.


Generate a CAB file, add it as a stream to the MSI file, put it into the Media table, and remove the generated file from the disk.

34.1.7. Directory Objects

class msilib.Directory(database, cab, basedir, physical, logical, default[, componentflags])

Create a new directory in the Directory table. There is a current component at each point in time for the directory, which is either explicitly created through start_component(), or implicitly when files are added for the first time. Files are added into the current component, and into the cab file. To create a directory, a base directory object needs to be specified (can be None), the path to the physical directory, and a logical directory name. default specifies the DefaultDir slot in the directory table. componentflags specifies the default flags that new components get.

start_component(component=None, feature=None, flags=None, keyfile=None, uuid=None)

Add an entry to the Component table, and make this component the current component for this directory. If no component name is given, the directory name is used. If no feature is given, the current feature is used. If no flags are given, the directory’s default flags are used. If no keyfile is given, the KeyPath is left null in the Component table.

add_file(file, src=None, version=None, language=None)

Add a file to the current component of the directory, starting a new one if there is no current component. By default, the file name in the source and the file table will be identical. If the src file is specified, it is interpreted relative to the current directory. Optionally, a version and a language can be specified for the entry in the File table.

glob(pattern, exclude=None)

Add a list of files to the current component as specified in the glob pattern. Individual files can be excluded in the exclude list.


Remove .pyc files on uninstall.

34.1.8. Features

class msilib.Feature(db, id, title, desc, display, level=1, parent=None, directory=None, attributes=0)

Add a new record to the Feature table, using the values id, parent.id, title, desc, display, level, directory, and attributes. The resulting feature object can be passed to the start_component() method of Directory.


Make this feature the current feature of msilib. New components are automatically added to the default feature, unless a feature is explicitly specified.

See also

Feature Table

34.1.9. GUI classes

msilib provides several classes that wrap the GUI tables in an MSI database. However, no standard user interface is provided; use bdist_msi to create MSI files with a user-interface for installing Python packages.

class msilib.Control(dlg, name)

Base class of the dialog controls. dlg is the dialog object the control belongs to, and name is the control’s name.

event(event, argument, condition=1, ordering=None)

Make an entry into the ControlEvent table for this control.

mapping(event, attribute)

Make an entry into the EventMapping table for this control.

condition(action, condition)

Make an entry into the ControlCondition table for this control.

class msilib.RadioButtonGroup(dlg, name, property)

Create a radio button control named name. property is the installer property that gets set when a radio button is selected.

add(name, x, y, width, height, text, value=None)

Add a radio button named name to the group, at the coordinates x, y, width, height, and with the label text. If value is None, it defaults to name.

class msilib.Dialog(db, name, x, y, w, h, attr, title, first, default, cancel)

Return a new Dialog object. An entry in the Dialog table is made, with the specified coordinates, dialog attributes, title, name of the first, default, and cancel controls.

control(name, type, x, y, width, height, attributes, property, text, control_next, help)

Return a new Control object. An entry in the Control table is made with the specified parameters.

This is a generic method; for specific types, specialized methods are provided.

text(name, x, y, width, height, attributes, text)

Add and return a Text control.

bitmap(name, x, y, width, height, text)

Add and return a Bitmap control.

line(name, x, y, width, height)

Add and return a Line control.

pushbutton(name, x, y, width, height, attributes, text, next_control)

Add and return a PushButton control.

radiogroup(name, x, y, width, height, attributes, property, text, next_control)

Add and return a RadioButtonGroup control.

checkbox(name, x, y, width, height, attributes, property, text, next_control)

Add and return a CheckBox control.

34.1.10. Precomputed tables

msilib provides a few subpackages that contain only schema and table definitions. Currently, these definitions are based on MSI version 2.0.


This is the standard MSI schema for MSI 2.0, with the tables variable providing a list of table definitions, and _Validation_records providing the data for MSI validation.


This module contains table contents for the standard sequence tables: AdminExecuteSequence, AdminUISequence, AdvtExecuteSequence, InstallExecuteSequence, and InstallUISequence.


This module contains definitions for the UIText and ActionText tables, for the standard installer actions.