firestore_helpers library

Classes

Area

Defines the search area by a circle center / radiusInKilometers Based on the limitations of FireStore we can only search in rectangles which means that from this definition a final search square is calculated that contains the circle

GeoBoundingBox

Defines the boundingbox for the query based on its south-west and north-east corners

OrderConstraint

Used by buildQuery to define how the results should be ordered. The fields corespond to the possisble parameters of Firestore`s oderby() method. Using OrderConstraint almost always requires to create an index for this field. Check your debug output for a message from FireStore with a link to create them

QueryConstraint

Used by buildQuery and getDataInArea to define a list of constraints. Important besides the field property not more than one of the others can ne !=null. They corespond to the possisble parameters of Firestore`s where() method. Using QueryConstraint almost always requires to create an index for this field. Check your debug output for a message from FireStore with a link to create them

Functions

boundingBoxCoordinates(Area area) → GeoBoundingBox

Calculates the SW and NE corners of a bounding box around a center point for a given radius; area with the center given as .latitude and .longitude and the radius of the box (in kilometers)

buildQuery({required Query collection, List<QueryConstraint>? constraints, List<OrderConstraint>? orderBy}) → Query

Builds a query dynamically based on a list of QueryConstraint and orders the result based on a list of OrderConstraint. collection : the source collection for the new query constraints : a list of constraints that should be applied to the collection. orderBy : a list of order constraints that should be applied to the collection after the filtering by constraints was done. Important all limitation of FireStore apply for this method two on how you can query fields in collections and order them.

coordinatesValid(double latitude, double longitude) → bool

Checks if these coordinates are valid geo coordinates. latitude The latitude must be in the range -90, 90 longitude The longitude must be in the range -180, 180 returns true if these are valid geo coordinates

degreesToRadians(double degrees) → double

distanceInKilometers(GeoPoint p1, GeoPoint p2) → double

Calculates the distance, in kilometers, between two locations, via the Haversine formula. Note that this is approximate due to the fact that the Earth's radius varies between 6356.752 km and 6378.137 km. p1 The first location given p2 The second location given return the distance, in kilometers, between the two locations.

distanceInKilometers2(GeoPoint p1, GeoPoint p2) → double

geoPointValid(GeoPoint point) → bool

Checks if the coordinates of a GeopPoint are valid geo coordinates. latitude The latitude must be in the range -90, 90 longitude The longitude must be in the range -180, 180 returns true if these are valid geo coordinates

getDataFromQuery<T>({required Query query, required DocumentMapper<T> mapper, List<ItemFilter<T>>? clientSidefilters, ItemComparer<T>? orderComparer}) → Stream<List<T>>

Convenience Method to access the data of a Query as a stream while applying a mapping function on each document with optional client side filtering and sorting qery : the data source mapper : mapping function that gets applied to every document in the query. Typically used to deserialize the Map returned from FireStore clientSideFilters : optional list of filter functions that execute a .where() on the result on the client side orderComparer : optional comparisson function. If provided your resulting data will be sorted based on it on the client

getDataInArea<T>({required Area area, required Query source, required DocumentMapper<T> mapper, required String locationFieldNameInDB, LocationAccessor<T>? locationAccessor, List<ItemFilter<T>>? clientSidefilters, DistanceMapper<T>? distanceMapper, DistanceAccessor<T>? distanceAccessor, bool sortDecending = false, List<QueryConstraint>? serverSideConstraints, List<OrderConstraint>? serverSideOrdering}) → Stream<List<T>>

Provides as Stream of lists of data items of type T that have a location field in a specified area sorted by the distance of to the areas center. area : The area that constraints the query source : The source FireStore document collection mapper : mapping function that gets applied to every document in the query. Typically used to deserialize the Map returned from FireStore locationFieldInDb : The name of the data field in your FireStore document. Need to make the location based search on the server side locationAccessor : As this is a generic function it cannot know where your location is stored in you generic type. optional if you don't use distanceMapper and don't want to sort by distance Therefore pass a function that returns a valur from the location field inside your generic type. distanceMapper : optional mapper that gets the distance to the center of the area passed to give you the chance to save this inside your item if you use a distanceMapper you HAVE to pass locationAccessor clientSideFilters : optional list of filter functions that execute a .where() on the result on the client side distanceAccessor : if you have stored the distance using a distanceMapper passing this accessor function will prevent additional distance computing for sorting. sortDecending : if the resulting list should be sorted descending by the distance to the area's center. If you don't provide loacationAccessor or distanceAccessor no sorting is done. This Sorting is done one the client side serverSideConstraints : If you need some serverside filtering besides the Area pass a list of QueryConstraint serverSideOrdering : If you need some serverside ordering you can pass a List of OrderConstraints Using serverSideConstraints or serverSideOrdering almost always requires to create an index for this field. Check your debug output for a message from FireStore with a link to create them

getLocationsConstraint(String fieldName, Area area) → List<QueryConstraint>

Creates the necessary constraints to query for items in a FireStore collection that are inside a specific range from a center point fieldName : the name of the field in FireStore where the location of the items is stored area : Area within that the returned items should be

kilometersToLongitudeDegrees(double distance, double latitude) → double

Calculates the number of degrees a given distance is at a given latitude. distance The distance to convert. latitude The latitude at which to calculate. returns the number of degrees the distance corresponds to.

wrapLongitude(double longitude) → double

Wraps the longitude to -180,180.

Typedefs

DistanceAccessor<T> = double Function(T item)

function typse used to access the distance field that contains the distance to the target inside the generic type

DistanceMapper<T> = T Function(T item, double itemsDistance)

DocumentMapper<T> = T? Function(DocumentSnapshot document)

ItemComparer<T> = int Function(T item1, T item2)

ItemFilter<T> = bool Function(T)

LocationAccessor<T> = GeoPoint Function(T item)

function typse used to acces the field that contains the loaction inside the generic type