serializers

measurement.serializers

Classes

MeasurementDataDownloadRequestSerializer

Bases: Serializer

Serializer for validating measurement data download requests.

Functions

validate(attrs)

Validate the request data.

Source code in measurement/serializers.py

def validate(self, attrs):
    """Validate the request data."""
    if attrs["start_date"] > attrs["end_date"]:
        raise serializers.ValidationError(
            {"end_date": "End date must be after start date."}
        )

    # Validate that the variable is available for the station
    station = attrs["station"]
    variable = attrs["variable"]
    if variable.variable_code not in station.variables_list:
        raise serializers.ValidationError(
            {
                "variable": f"Variable '{variable.variable_code}' is not available "
                f"for station '{station.station_code}'."
            }
        )

    return attrs

MeasurementDataDownloadResponseSerializer

Bases: Serializer

Serializer for measurement data response.

Station

Bases: PermissionsBase

Main representation of a station, including several metadata.

Attributes:

Name	Type	Description
visibility	str	Visibility level of the object, including an "internal" option.
station_id	int	Primary key.
station_code	str	Unique code for the station.
station_name	str	Brief description of the station.
station_type	StationType	Type of the station.
country	Country	Country where the station is located.
region	Region	Region within the Country where the station is located.
ecosystem	Ecosystem	Ecosystem associated with the station.
institution	Institution	Institutional partner responsible for the station.
place_basin	PlaceBasin	Place-Basin association.
station_state	bool	Is the station operational?
timezone	str	Timezone of the station.
station_latitude	Decimal	Latitude of the station, in degrees [-90 to 90].
station_longitude	Decimal	Longitude of the station, in degrees [-180 to 180].
station_altitude	int	Altitude of the station.
influence_km	Decimal	Area of influence in km2.
station_file	ImageField	Photography of the station.
station_external	bool	Is the station external?
variables	str	Comma-separated list of variables measured by the station.

Attributes

variables_list property

Return the list of variables measured by the station.

Only variables with data in the database are returned.

Returns:

Type	Description
list[str]	list[str]: List of variables measured by the station.

Functions

__str__()

Return the station code.

Source code in station/models.py

def __str__(self) -> str:
    """Return the station code."""
    return str(self.station_code)

get_absolute_url()

Return the absolute url of the station.

Source code in station/models.py

def get_absolute_url(self) -> str:
    """Return the absolute url of the station."""
    return reverse("station:station_detail", kwargs={"pk": self.pk})

set_object_permissions()

Set object-level permissions.

This method is called by the save method of the model to set the object-level permissions based on the visibility level of the object. In addition to the standard permissions for the station, the view_measurements permission is set which controls who can view the measurements associated to the station.

Source code in station/models.py

def set_object_permissions(self) -> None:
    """Set object-level permissions.

    This method is called by the save method of the model to set the object-level
    permissions based on the visibility level of the object. In addition to the
    standard permissions for the station, the view_measurements permission is set
    which controls who can view the measurements associated to the station.
    """
    super().set_object_permissions()

    standard_group = Group.objects.get(name="Standard")
    anonymous_user = get_anonymous_user()

    # Assign view_measurements permission based on permissions level
    if self.visibility == "public":
        assign_perm("view_measurements", standard_group, self)
        assign_perm("view_measurements", anonymous_user, self)
        if self.owner:
            remove_perm("view_measurements", self.owner, self)
    elif self.visibility == "internal":
        assign_perm("view_measurements", standard_group, self)
        remove_perm("view_measurements", anonymous_user, self)
        if self.owner:
            remove_perm("view_measurements", self.owner, self)
    elif self.visibility == "private":
        remove_perm("view_measurements", standard_group, self)
        remove_perm("view_measurements", anonymous_user, self)
        if self.owner:
            assign_perm("view_measurements", self.owner, self)

Variable

Bases: PermissionsBase

A variable with a physical meaning.

Such as precipitation, wind speed, wind direction, soil moisture, including the associated unit. It also includes metadata to help identify what is a reasonable value for the data, to flag outliers and to help with the validation process.

The nature of the variable can be one of the following:

• sum: Cumulative value over a period of time.
• average: Average value over a period of time.
• value: One-off value.

Attributes:

Name	Type	Description
variable_id	AutoField	Primary key.
variable_code	CharField	Code of the variable, eg. airtemperature.
name	CharField	Human-readable name of the variable, eg. Air temperature.
unit	ForeignKey	Unit of the variable.
maximum	DecimalField	Maximum value allowed for the variable.
minimum	DecimalField	Minimum value allowed for the variable.
diff_error	DecimalField	If two sequential values in the time-series data of this variable differ by more than this value, the validation process can mark this with an error flag.
outlier_limit	DecimalField	The statistical deviation for defining outliers, in times the standard deviation (sigma).
null_limit	DecimalField	The max % of null values (missing, caused by e.g. equipment malfunction) allowed for hourly, daily, monthly data. Cumulative values are not deemed trustworthy if the number of missing values in a given period is greater than the null_limit.
nature	CharField	Nature of the variable, eg. if it represents a one-off value, the average over a period of time or the cumulative value over a period

Attributes

is_cumulative property

Return True if the nature of the variable is sum.

Functions

__str__()

Return the string representation of the object.

Source code in variable/models.py

def __str__(self) -> str:
    """Return the string representation of the object."""
    return str(self.name)

clean()

Validate the model fields.

Source code in variable/models.py

def clean(self) -> None:
    """Validate the model fields."""
    if self.maximum < self.minimum:
        raise ValidationError(
            {"maximum": "The maximum value must be greater than the minimum value."}
        )
    if not self.variable_code.isidentifier():
        raise ValidationError(
            {
                "variable_code": "The variable code must be a valid Python "
                "identifier. Only letters, numbers and underscores are allowed, and"
                " it cannot start with a number."
            }
        )
    return super().clean()

get_absolute_url()

Get the absolute URL of the object.

Source code in variable/models.py

def get_absolute_url(self) -> str:
    """Get the absolute URL of the object."""
    return reverse("variable:variable_detail", kwargs={"pk": self.pk})