WIP: Internationalization and localization

babel.cfg

@@ -0,0 +1,8 @@
+[extractors]
+yaml = ohsome_quality_api.utils:pybabel_yaml_extractor
+
+[python: **.py]
+
+[yaml: **.yaml]
+keys = name,description,red,yellow,green,undefined,result_description
+encoding = utf-8

docs/i18n.md

@@ -0,0 +1,17 @@
+# Internationalization (I18N) and Localization (I10N)
+
+## Babel
+
+Add a new locale:
+```bash
+poetry run pybabel extract -F babel.cfg -o messages.pot .
+pybabel init -i messages.pot -d ohsome_quality_api/locale -l de
+pybabel compile -d ohsome_quality_api/locale
+```
+
+Update a existing locale:
+```bash
+poetry run pybabel extract -F babel.cfg -o messages.pot .
+pybabel update -i messages.pot -d ohsome_quality_api/locale
+pybabel compile -d ohsome_quality_api/locale
+```

ohsome_quality_api/api/api.py

@@ -3,7 +3,7 @@
 import os
 from typing import Any, Union
 
-from fastapi import FastAPI, HTTPException, Request, status
+from fastapi import Depends, FastAPI, HTTPException, Request, status
 from fastapi.encoders import jsonable_encoder
 from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
@@ -13,6 +13,7 @@
     get_swagger_ui_oauth2_redirect_html,
 )
 from fastapi.responses import JSONResponse
+from fastapi_i18n import i18n
 from geojson import FeatureCollection
 from starlette.exceptions import HTTPException as StarletteHTTPException
 from starlette.staticfiles import StaticFiles
@@ -114,6 +115,7 @@
     openapi_tags=TAGS_METADATA,
     docs_url=None,
     redoc_url=None,
+    dependencies=[Depends(i18n)],
 )
 
 app.add_middleware(

ohsome_quality_api/indicators/attribute_completeness/indicator.py

@@ -98,17 +98,17 @@ def calculate(self) -> None:
         if self.result.value >= self.threshold_yellow:
             self.result.class_ = 5
             self.result.description = (
-                self.description + self.templates.label_description["green"]
+                self.description + self.templates.label_description.green
             )
         elif self.threshold_yellow > self.result.value >= self.threshold_red:
             self.result.class_ = 3
             self.result.description = (
-                self.description + self.templates.label_description["yellow"]
+                self.description + self.templates.label_description.yellow
             )
         else:
             self.result.class_ = 1
             self.result.description = (
-                self.description + self.templates.label_description["red"]
+                self.description + self.templates.label_description.red
             )
 
     def create_description(self):

ohsome_quality_api/indicators/base.py

@@ -37,7 +37,7 @@ def __init__(
         self.topic: Topic = topic
         self.feature: Feature = feature
         self.result: Result = Result(
-            description=self.templates.label_description["undefined"],
+            description=self.templates.label_description.undefined
         )
         self._get_default_figure()
 

ohsome_quality_api/indicators/building_comparison/indicator.py

@@ -130,13 +130,19 @@ def calculate(self) -> None:
                 self.result.class_ = 3
             elif self.th_low > self.result.value >= 0:
                 self.result.class_ = 1
-            label_description = self.templates.label_description[self.result.label]
+            label_description = getattr(
+                self.templates.label_description, self.result.label
+            )
             self.result.description = " ".join((label_description, result_description))
         elif major_edge_case:
-            label_description = self.templates.label_description[self.result.label]
+            label_description = getattr(
+                self.templates.label_description, self.result.label
+            )
             self.result.description = " ".join((label_description, result_description))
         else:
-            label_description = self.templates.label_description[self.result.label]
+            label_description = getattr(
+                self.templates.label_description, self.result.label
+            )
             edge_case = (
                 "OSM has substantivly more buildings than the reference datasets. The "
                 "reference dataset is likely to miss many buildings."

ohsome_quality_api/indicators/currentness/indicator.py

@@ -158,7 +158,7 @@ def calculate(self):
         else:
             self.result.class_ = 1
 
-        label_description = self.templates.label_description[self.result.label]
+        label_description = getattr(self.templates.label_description, self.result.label)
         self.result.description += Template(
             self.templates.result_description
         ).substitute(

ohsome_quality_api/indicators/density/indicator.py

@@ -46,18 +46,18 @@ def calculate(self) -> None:
         if self.result.value >= self.threshold_yellow:
             self.result.class_ = 5
             self.result.description = (
-                description + self.templates.label_description["green"]
+                description + self.templates.label_description.green
             )
         else:
             if self.result.value > self.threshold_red:
                 self.result.class_ = 3
                 self.result.description = (
-                    description + self.templates.label_description["yellow"]
+                    description + self.templates.label_description.yellow
                 )
             else:
                 self.result.class_ = 1
                 self.result.description = (
-                    description + self.templates.label_description["red"]
+                    description + self.templates.label_description.red
                 )
 
     def create_figure(self) -> None:

ohsome_quality_api/indicators/mapping_saturation/indicator.py

@@ -151,8 +151,8 @@ def calculate(self) -> None:  # noqa: C901
         description = Template(self.templates.result_description).substitute(
             saturation=round(self.result.value * 100, 2)
         )
-        self.result.description = (
-            description + self.templates.label_description[self.result.label]
+        self.result.description = description + getattr(
+            self.templates.label_description, self.result.label
         )
 
     def create_figure(self) -> None:

ohsome_quality_api/indicators/minimal/indicator.py

@@ -25,9 +25,7 @@ async def preprocess(self) -> None:
     def calculate(self) -> None:
         description = Template(self.templates.result_description).substitute()
         self.result.value = 1.0
-        self.result.description = (
-            description + self.templates.label_description["green"]
-        )
+        self.result.description = description + self.templates.label_description.green
 
     def create_figure(self) -> None:
         # Do nothing ...

ohsome_quality_api/indicators/models.py

@@ -1,7 +1,8 @@
 from datetime import datetime, timezone
 from typing import Literal
 
-from pydantic import BaseModel, ConfigDict, Field, computed_field
+from fastapi_i18n import _
+from pydantic import BaseModel, ConfigDict, Field, computed_field, field_validator
 
 from ohsome_quality_api.projects.definitions import ProjectEnum
 from ohsome_quality_api.quality_dimensions.definitions import QualityDimensionEnum
@@ -23,13 +24,35 @@ class IndicatorMetadata(BaseModel):
         populate_by_name=True,
     )
 
+    @field_validator("name", "description", mode="before")
+    @classmethod
+    def translate(cls, value: str) -> str:
+        return _(value)
+
+
+class LabelDescription(BaseModel):
+    green: str
+    yellow: str
+    red: str
+    undefined: str
+
+    @field_validator("green", "yellow", "red", "undefined", mode="before")
+    @classmethod
+    def translate(cls, value: str) -> str:
+        return _(value)
+
 
 class IndicatorTemplates(BaseModel):
     """Result text templates of an indicator as defined in the templates.yaml file."""
 
-    label_description: dict[str, str]
+    label_description: LabelDescription
     result_description: str
 
+    @field_validator("result_description", mode="before")
+    @classmethod
+    def translate(cls, value: str) -> str:
+        return _(value)
+
 
 class Result(BaseModel):
     """The result of the Indicator.

ohsome_quality_api/indicators/road_comparison/indicator.py

@@ -138,7 +138,7 @@ def calculate(self) -> None:
             elif self.th_low > self.result.value >= 0:
                 self.result.class_ = 1
 
-        label_description = self.templates.label_description[self.result.label]
+        label_description = getattr(self.templates.label_description, self.result.label)
         self.result.description += label_description
         # remove double white spaces
         self.result.description = " ".join(self.result.description.split())