Follow

Read the README file for a description of Follow application.

Importing this module makes all application scope components available. In addition, you probably will need to import individual fetchers, middlewares and digesters.

Documentation

data Recipe m

A recipe is a specification of a complete strategy to create the content to follow a subject.

Constructors

Recipe

Fields

• rSubject :: Subject

  The subject being followed.

• rSteps :: [Step m]

  List of steps to be applied.

• rMiddlewares :: [Middleware]

  List of middlewares to apply to the result of all steps.

Instances

(MonadThrow m, MonadHttp m) => FromJSON (Recipe m)

  subject: # See Subject instance
  steps:
    -
      - # See Fetched instance
      -
        - # See Middleware instance
  middlewares:"
    - # See Middleware instance
 

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser (Recipe m)

parseJSONList :: Value -> Parser [Recipe m]

data Subject

Subject being followed. The whole idea of Follow is being able to build strategies to gather URIs for the content published about any subject.

Constructors

Subject

Fields

• sTitle :: Text

  Title.

• sDescription :: Text

  Description.

• sTags :: [Text]

  List of tags.

Instances

Eq Subject

Defined in Follow.Types

Methods

(==) :: Subject -> Subject -> Bool

(/=) :: Subject -> Subject -> Bool

Show Subject

Defined in Follow.Types

Methods

showsPrec :: Int -> Subject -> ShowS

show :: Subject -> String

showList :: [Subject] -> ShowS

FromJSON Subject

  title: Title
  description: Description
  tags: [tag_1, tag_2]
  

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser Subject

parseJSONList :: Value -> Parser [Subject]

data Entry

An item of content that has been published somewhere.

Constructors

Entry

Fields

• eURI :: Maybe Text

  URI that identifies the location of the item.

• eGUID :: Maybe Text

  Unique identifier.

• eTitle :: Maybe Text

  Title.

• eDescription :: Maybe Text

  Description.

• eAuthor :: Maybe Text

  Author.

• ePublishDate :: Maybe LocalTime

  Item publish date.

Instances

Eq Entry

Defined in Follow.Types

Methods

(==) :: Entry -> Entry -> Bool

(/=) :: Entry -> Entry -> Bool

Show Entry

Defined in Follow.Types

Methods

showsPrec :: Int -> Entry -> ShowS

show :: Entry -> String

showList :: [Entry] -> ShowS

FromJSON ComparisonFunction

  type: by_field
  options:
    field: title
  

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser ComparisonFunction

parseJSONList :: Value -> Parser [ComparisonFunction]

FromJSON Predicate

  type: equal
  options:
    field: title
    value: Title
  

or

  type: less
  options:
    field: publish_date
    value: 2018-08-08 00:00:00
  

or

  type: greater
  options:
    field: publish_date
    value: 2018-08-08 00:00:00
  

or

  type: infix
  options:
    field: title
    value: something
  

or

  type: prefix
  options:
    field: title
    value: The
  

or

  type: suffix
  options:
    field: title
    value: end
  

or

  type: not
  options:
    operator: # See Predicate instance
  

or

  type: and
  options:
    operator1: # See Predicate instance
    operator2: # See Predicate instance
  

or

  type: or
  options:
    operator1: # See Predicate instance
    operator2: # See Predicate instance
  

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser Predicate

parseJSONList :: Value -> Parser [Predicate]

(MonadThrow m, MonadHttp m) => FromJSON (Fetched m)

  type: feed
  options:
    url: http://someurl.com
  

or

  type: webscraping
  options:
    url: http://someurl.com
    selector: # See Selector instance
  

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser (Fetched m)

parseJSONList :: Value -> Parser [Fetched m]

type Fetched m = m [Entry]

Entries fetched usually from the outside world.

data Directory

Gathering of Item published for some Subject.

Constructors

Directory

Fields

• dSubject :: Subject

  The subject.

• dEntries :: [Entry]

  The list of entries.

Instances

Eq Directory

Defined in Follow.Types

Methods

(==) :: Directory -> Directory -> Bool

(/=) :: Directory -> Directory -> Bool

Show Directory

Defined in Follow.Types

Methods

showsPrec :: Int -> Directory -> ShowS

show :: Directory -> String

showList :: [Directory] -> ShowS

FromJSON Middleware

  type: decode
  options:
    encoding: # See Encoding instance
 

or

  type: sort
  options:
    function: # See ComparisonInstance instance
 

or

  type: filter
  options:
    operation: # See Predicate instance
 

Defined in Follow.Parser

Methods

parseJSON :: Value -> Parser Middleware

parseJSONList :: Value -> Parser [Middleware]

type Step m = (Fetched m, [Middleware])

A list of middlewares to be applied to some fetched entries.

type Middleware = Directory -> Directory

Middleware does something to a directory.

type Digester a = Directory -> a

Digesters are strategies to transform a directory into something to be consumed by an end user.

directoryFromRecipe :: MonadThrow m => Recipe m -> m Directory

Builds a directory from the specification stored in a recipe

directoryFromFetched :: MonadThrow m => m [Entry] -> Subject -> m Directory

Helper to build a directory from a subject and a list of fetched entries.

applyMiddlewares :: [Middleware] -> Directory -> Directory

Applies, from left to right, given middlewares to the directory.

applySteps :: MonadThrow m => Directory -> [Step m] -> m Directory

Applies, from left to right, a list of steps to given directory.

emptyDirectory :: Subject -> Directory

Creates a directory with given subject and no entries.

mergeEntries :: Directory -> [Entry] -> Directory

Merges a list of entries into a Directory, keeping only first appearance of duplicates.