docs: rework library getting started

[nominatim.git] / docs / library / Getting-Started.md

diff --git a/docs/library/Getting-Started.md b/docs/library/Getting-Started.md
index 22d9681d6fd119c42e67a5b605e47633a870e5ed..6206022ff2bcafb0356287b55fcbe2169bbd55e3 100644 (file)
--- a/docs/library/Getting-Started.md
+++ b/docs/library/Getting-Started.md
@@ -1,16 +1,21 @@
 # Getting Started
 
 # Getting Started
 

-The Nominatim search frontend can directly be used as a Python library in
-scripts and applications. When you have imported your own Nominatim database,
-then it is no longer necessary to run a full web service for it and access
-the database through http requests. There are
-also less constraints on the kinds of data that can be accessed. The library
-allows to get access to more detailed information about the objects saved
-in the database.
-
-!!! danger
-    The library interface is currently in an experimental stage. There might
-    be some smaller adjustments to the public interface until the next version.
+The Nominatim search frontend is implemented as a Python library and can as
+such directly be used in Python scripts and applications. You don't need to
+set up a web frontend and access it through HTTP calls. The library gives
+direct access to the Nominatim database through similar search functions as
+offered by the web API. In addition, it will give you a more complete and
+detailed view on the search objects stored in the database.
+
+!!! warning
+
+    The Nominatim library is used for accessing a local Nominatim database.
+    It is not meant to be used against web services of Nominatim like the
+    one on https://nominatim.openstreetmap.org. If you need a Python library
+    to access these web services, have a look at
+    [GeoPy](https://geopy.readthedocs.io). Don't forget to consult the
+    usage policy of the service you want to use before accessing such
+    a web service.

 
 ## Installation
 
 
 ## Installation
 


@@ -18,12 +23,16 @@ To use the Nominatim library, you need access to a local Nominatim database.
 Follow the [installation](../admin/Installation.md) and
 [import](../admin/Import.md) instructions to set up your database.
 
 Follow the [installation](../admin/Installation.md) and
 [import](../admin/Import.md) instructions to set up your database.
 

-The Nominatim frontend library is contained in the 'nominatim-api' package.
+The Nominatim frontend library is contained in the Python package `nominatim-api`.
+You can install the latest released version directly from pip:
+
+    pip install nominatim-api
+

 To install the package from the source tree directly, run:
 
     pip install packaging/nominatim-api
 
 To install the package from the source tree directly, run:
 
     pip install packaging/nominatim-api
 

-Usually, you would want to run this in a virtual environment.
+Usually you would want to run this in a virtual environment.

 
 ### A simple search example
 
 
 ### A simple search example
 


@@ -36,15 +45,13 @@ This code snippet implements a simple search for the town of 'Brugge':
 !!! example
     === "NominatimAPIAsync"
         ``` python
 !!! example
     === "NominatimAPIAsync"
         ``` python

-        from pathlib import Path

         import asyncio
 
         import nominatim_api as napi
 
         async def search(query):
         import asyncio
 
         import nominatim_api as napi
 
         async def search(query):

-            api = napi.NominatimAPIAsync(Path('.'))
-
-            return await api.search(query)
+            async with napi.NominatimAPIAsync() as api:
+                return await api.search(query)

 
         results = asyncio.run(search('Brugge'))
         if not results:
 
         results = asyncio.run(search('Brugge'))
         if not results:


@@ -55,13 +62,10 @@ This code snippet implements a simple search for the town of 'Brugge':
 
     === "NominatimAPI"
         ``` python
 
     === "NominatimAPI"
         ``` python

-        from pathlib import Path
-

         import nominatim_api as napi
 
         import nominatim_api as napi
 

-        api = napi.NominatimAPI(Path('.'))
-
-        results = api.search('Brugge')
+        with napi.NominatimAPI() as api:
+            results = api.search('Brugge')

 
         if not results:
             print('Cannot find Brugge')
 
         if not results:
             print('Cannot find Brugge')


@@ -93,25 +97,31 @@ The same configuration mechanism is used with the
 Nominatim API library. You should therefore be sure you are familiar with
 the section.
 
 Nominatim API library. You should therefore be sure you are familiar with
 the section.
 

-The constructor of the 'Nominatim API class' takes one mandatory parameter:
-the path to the [project directory](../admin/Import.md#creating-the-project-directory).
-You should have set up this directory as part of the Nominatim import.
-Any configuration found in the `.env` file in this directory will automatically
-used.
+There are three different ways, how configuration options can be set for
+a 'Nominatim API class'. When you have set up your Nominatim database, you
+have normally created a [project directory](../admin/Import.md#creating-the-project-directory)
+which stores the various configuration and customization files that Nominatim
+needs. You may pass the location of the project directory to your
+'Nominatim API class' constructor and it will read the .env file in the
+directory and set the configuration accordingly.

 
 You may also configure Nominatim by setting environment variables.
 
 You may also configure Nominatim by setting environment variables.

-Normally, Nominatim will check the operating system environment. This can be
-overwritten by giving the constructor a dictionary of configuration parameters.
+Normally Nominatim will check the operating system environment. Lets
+say you want to look up 'Brugge' in the special database named 'belgium' instead of the
+standard 'nominatim' database. You can run the example script above like this:

 
 

-Let us look up 'Brugge' in the special database named 'belgium' instead of the
-standard 'nominatim' database:
+```
+NOMINATIM_DATABASE_DSN=pgsql:dbname=belgium python3 example.py
+```
+
+The third option to configure the library is to hand in the configuration
+parameters into the 'Nominatim API class'. Changing the database would look
+like this:

 
 !!! example
     === "NominatimAPIAsync"
         ``` python
 
 !!! example
     === "NominatimAPIAsync"
         ``` python

-        from pathlib import Path

         import asyncio
         import asyncio

-

         import nominatim_api as napi
 
         config_params = {
         import nominatim_api as napi
 
         config_params = {


@@ -119,50 +129,53 @@ standard 'nominatim' database:
         }
 
         async def search(query):
         }
 
         async def search(query):

-            api = napi.NominatimAPIAsync(Path('.'), environ=config_params)
-
-            return await api.search(query)
+            async with napi.NominatimAPIAsync(environ=config_params) as api:
+                return await api.search(query)

 
         results = asyncio.run(search('Brugge'))
         ```
 
     === "NominatimAPI"
         ``` python
 
         results = asyncio.run(search('Brugge'))
         ```
 
     === "NominatimAPI"
         ``` python

-        from pathlib import Path
-

         import nominatim_api as napi
 
         config_params = {
             'NOMINATIM_DATABASE_DSN': 'pgsql:dbname=belgium'
         }
 
         import nominatim_api as napi
 
         config_params = {
             'NOMINATIM_DATABASE_DSN': 'pgsql:dbname=belgium'
         }
 

-        api = napi.NominatimAPI(Path('.'), environ=config_params)
-
-        results = api.search('Brugge')
+        with napi.NominatimAPI(environ=config_params) as api:
+            results = api.search('Brugge')

         ```
 
         ```
 

+When the `environ` parameter is given, then only configuration variables
+from this dictionary will be used.
+

 ### Presenting results to humans
 
 ### Presenting results to humans
 

-All search functions return the raw results from the database. There is no
-full human-readable label. To create such a label, you need two things:
+All search functions return full result objects from the database. Such a
+result object contains lots of details: names, address information, OSM tags etc.
+This gives you lots of flexibility what to do with the results.
+
+One of the most common things to get is some kind of human-readable label
+that describes the result in a compact form. Usually this would be the name
+of the object and some parts of the address to explain where in the world
+it is. To create such a label, you need two things:

 
 * the address details of the place
 
 * the address details of the place

-* adapt the result to the language you wish to use for display
+* all names for the label adapted to the language you wish to use for display

 
 Again searching for 'Brugge', this time with a nicely formatted result:
 
 !!! example
     === "NominatimAPIAsync"
         ``` python
 
 Again searching for 'Brugge', this time with a nicely formatted result:
 
 !!! example
     === "NominatimAPIAsync"
         ``` python

-        from pathlib import Path

         import asyncio
 
         import nominatim_api as napi
 
         async def search(query):
         import asyncio
 
         import nominatim_api as napi
 
         async def search(query):

-            api = napi.NominatimAPIAsync(Path('.'))
-
-            return await api.search(query, address_details=True)
+            async with napi.NominatimAPIAsync() as api:
+                return await api.search(query, address_details=True)

 
         results = asyncio.run(search('Brugge'))
 
 
         results = asyncio.run(search('Brugge'))
 


@@ -174,13 +187,10 @@ Again searching for 'Brugge', this time with a nicely formatted result:
 
     === "NominatimAPI"
         ``` python
 
     === "NominatimAPI"
         ``` python

-        from pathlib import Path
-

         import nominatim_api as napi
 
         import nominatim_api as napi
 

-        api = napi.NominatimAPI(Path('.'))
-
-        results = api.search('Brugge', address_details=True)
+        with napi.NominatimAPI() as api:
+            results = api.search('Brugge', address_details=True)

 
         locale = napi.Locales(['fr', 'en'])
         for i, result in enumerate(results):
 
         locale = napi.Locales(['fr', 'en'])
         for i, result in enumerate(results):


@@ -236,7 +246,7 @@ Bruges, Flandre-Occidentale, Flandre, Belgique
 
 This is a fairly simple way to create a human-readable description. The
 place information in `address_rows` contains further information about each
 
 This is a fairly simple way to create a human-readable description. The
 place information in `address_rows` contains further information about each

-place. For example, which OSM `adlin_level` was used, what category the place
+place. For example, which OSM `admin_level` was used, what category the place

 belongs to or what rank Nominatim has assigned. Use this to adapt the output
 to local address formats.
 
 belongs to or what rank Nominatim has assigned. Use this to adapt the output
 to local address formats.