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# python-aio-geojson-generic-client
[](https://github.com/exxamalte/python-aio-geojson-generic-client/actions?workflow=CI)
[](https://codecov.io/gh/exxamalte/python-aio-geojson-generic-client)
[](https://pypi.python.org/pypi/aio-geojson-generic-client)
[](https://pypi.python.org/pypi/aio-geojson-generic-client)
This library provides convenient async generic access to [GeoJSON](https://datatracker.ietf.org/doc/html/rfc7946) feeds.
## Installation
`pip install aio-geojson-generic-client`
## Usage
See below for examples of how this library can be used. After instantiating a
particular class - feed or feed manager - and supply the required parameters,
you can call `update` to retrieve the feed data. The return value
will be a tuple of a status code and the actual data in the form of a list of
feed entries specific to the selected feed.
Status Codes
* _OK_: Update went fine and data was retrieved. The library may still
return empty data, for example because no entries fulfilled the filter
criteria.
* _OK_NO_DATA_: Update went fine but no data was retrieved, for example
because the server indicated that there was not update since the last request.
* _ERROR_: Something went wrong during the update
**Parameters**
| Parameter | Description |
|--------------------|-------------------------------------------|
| `home_coordinates` | Coordinates (tuple of latitude/longitude) |
| `url` | URL of the GeoJSON feed |
**Supported Filters**
| Filter | | Description |
|------------|---------------------|-------------|
| Radius | `filter_radius` | Radius in kilometers around the home coordinates in which events from feed are included. |
**Example**
```python
import asyncio
from aiohttp import ClientSession
from aio_geojson_generic_client import GenericFeed
async def main() -> None:
async with ClientSession() as websession:
# Home Coordinates: Latitude: -33.0, Longitude: 150.0
# Filter radius: 50 km
feed = GenericFeed(websession,
(-33.0, 150.0),
"https://www.rfs.nsw.gov.au/feeds/majorIncidents.json",
filter_radius=50)
status, entries = await feed.update()
print(status)
print(entries)
asyncio.get_event_loop().run_until_complete(main())
```
## Feed entry properties
Each feed entry is populated with the following properties:
| Name | Description | Feed attribute |
|--------------------|-----------------------------------------------------------------------------------------------------|----------------------------------------------|
| geometries | All geometry details of this entry. | `geometry` |
| coordinates | Best coordinates (latitude, longitude) of this entry. | `geometry` |
| external_id | The unique public identifier for this incident. | `id`, `guid`, `title` or hash of coordinates |
| title | Title of this entry (if provided). | `title` |
| distance_to_home | Distance in km of this entry to the home coordinates. | n/a |
| publication_date | The publication date of the entry (if provided). | `pubDate` |
| properties | All properties defined for this entry. | `properties` |
## Feed Manager
The Feed Manager helps managing feed updates over time, by notifying the
consumer of the feed about new feed entries, updates and removed entries
compared to the last feed update.
* If the current feed update is the first one, then all feed entries will be
reported as new. The feed manager will keep track of all feed entries'
external IDs that it has successfully processed.
* If the current feed update is not the first one, then the feed manager will
produce three sets:
* Feed entries that were not in the previous feed update but are in the
current feed update will be reported as new.
* Feed entries that were in the previous feed update and are still in the
current feed update will be reported as to be updated.
* Feed entries that were in the previous feed update but are not in the
current feed update will be reported to be removed.
* If the current update fails, then all feed entries processed in the previous
feed update will be reported to be removed.
After a successful update from the feed, the feed manager provides two
different dates:
* `last_update` will be the timestamp of the last update from the feed
irrespective of whether it was successful or not.
* `last_update_successful` will be the timestamp of the last successful update
from the feed. This date may be useful if the consumer of this library wants
to treat intermittent errors from feed updates differently.
* `last_timestamp` (optional, depends on the feed data) will be the latest
timestamp extracted from the feed data.
This requires that the underlying feed data actually contains a suitable
date. This date may be useful if the consumer of this library wants to
process feed entries differently if they haven't actually been updated.
|
