How to extend

To introduce a new data access system, you have to write a new package inside the “parser” package; this new package must provide a subclass of the imdb.IMDb class which must define at least the following methods:

_search_movie(title)
To search for a given title; must return a list of (movieID, {movieData}) tuples.
_search_episode(title)
To search for a given episode title; must return a list of (movieID, {movieData}) tuples.
_search_person(name)
To search for a given name; must return a list of (movieID, {personData}) tuples.
_search_character(name)
To search for a given character’s name; must return a list of (characterID, {characterData}) tuples.
_search_company(name)
To search for a given company’s name; must return a list of (companyID, {companyData}) tuples.
get_movie_*(movieID)

A set of methods, one for every set of information defined for a Movie object; should return a dictionary with the relative information.

This dictionary can contain some optional keys:

  • ‘data’: must be a dictionary with the movie info
  • ‘titlesRefs’: a dictionary of ‘movie title’: movieObj pairs
  • ‘namesRefs’: a dictionary of ‘person name’: personObj pairs
get_person_*(personID)
A set of methods, one for every set of information defined for a Person object; should return a dictionary with the relative information.
get_character_*(characterID)
A set of methods, one for every set of information defined for a Character object; should return a dictionary with the relative information.
get_company_*(companyID)
A set of methods, one for every set of information defined for a Company object; should return a dictionary with the relative information.
_get_top_bottom_movies(kind)
Kind can be one of ‘top’ and ‘bottom’; returns the related list of movies.
_get_keyword(keyword)
Return a list of Movie objects with the given keyword.
_search_keyword(key)
Return a list of keywords similar to the given key.
get_imdbMovieID(movieID)
Convert the given movieID to a string representing the imdbID, as used by the IMDb web server (e.g.: ‘0094226’ for Brian De Palma’s “The Untouchables”).
get_imdbPersonID(personID)
Convert the given personID to a string representing the imdbID, as used by the IMDb web server (e.g.: ‘0000154’ for “Mel Gibson”).
get_imdbCharacterID(characterID)
Convert the given characterID to a string representing the imdbID, as used by the IMDb web server (e.g.: ‘0000001’ for “Jesse James”).
get_imdbCompanyID(companyID)
Convert the given companyID to a string representing the imdbID, as used by the IMDb web server (e.g.: ‘0071509’ for “Columbia Pictures [us]”).
_normalize_movieID(movieID)

Convert the provided movieID in a format suitable for internal use (e.g.: convert a string to a long int).

NOTE: As a rule of thumb you always need to provide a way to convert a “string representation of the movieID” into the internally used format, and the internally used format should always be converted to a string, in a way or another. Rationale: A movieID can be passed from the command line, or from a web browser.

_normalize_personID(personID)
idem
_normalize_characterID(characterID)
idem
_normalize_companyID(companyID)
idem
_get_real_movieID(movieID)
Return the true movieID; useful to handle title aliases.
_get_real_personID(personID)
idem
_get_real_characterID(characterID)
idem
_get_real_companyID(companyID)
idem

The class should raise the appropriate exceptions, when needed:

  • IMDbDataAccessError must be raised when you cannot access the resource you need to retrieve movie info or you’re unable to do a query (this is not the case when a query returns zero matches: in this situation an empty list must be returned).
  • IMDbParserError should be raised when an error occurred parsing some data.

Now you’ve to modify the imdb.IMDb function so that, when the right data access system is selected with the “accessSystem” parameter, an instance of your newly created class is returned.

For example, if you want to call your new data access system “mysql” (meaning that the data are stored in a mysql database), you have to add to the imdb.IMDb function something like:

if accessSystem == 'mysql':
    from parser.mysql import IMDbMysqlAccessSystem
    return IMDbMysqlAccessSystem(*arguments, **keywords)

where “parser.mysql” is the package you’ve created to access the local installation, and “IMDbMysqlAccessSystem” is the subclass of imdb.IMDbBase.

Then it’s possible to use the new data access system like:

from imdb import IMDb
i = IMDb(accessSystem='mysql')
results = i.search_movie('the matrix')
print(results)

Note

This is a somewhat misleading example: we already have a data access system for SQL database (it’s called ‘sql’ and it supports MySQL, amongst others). Maybe I’ll find a better example…

A specific data access system implementation can define its own methods. As an example, the IMDbHTTPAccessSystem that is in the parser.http package defines the method set_proxy() to manage the use a web proxy; you can use it this way:

from imdb import IMDb
i = IMDb(accessSystem='http') # the 'accessSystem' argument is not
                              # really needed, since "http" is the default.
i.set_proxy('http://localhost:8080/')

A list of special methods provided by the imdb.IMDbBase subclass, along with their description, is always available calling the get_special_methods() of the IMDb class:

i = IMDb(accessSystem='http')
print(i.get_special_methods())

will print a dictionary with the format:

{'method_name': 'method_description', ...}