Raspberry Pi Client

The Python code of this repository is for a Raspberry Pi. It enables the Raspberry Pi to connect to the Datapool web application. It connects to the web application via the Datapool processor SourcePot\Datapool\Processing\RemoteClient and it can be used within any data app.

'RemoteClient' receives requests from e.g. multiple Raspberry Pis containing data (status information, sensory data) and/or files (images, videos). The web application's answer to each request contains the settings for the respective Raspberry Pi.

First steps on the side of the Raspberry Pi

To setup the Raspberry Pi client you need to create a folder on your Raspberry Pi and copy the following three python files into this folder:

1. __init__.py,
2. datapoolclient.py and
3. sentinel.py

You will need to adjust the url in datapoolclient.py to the web address of your Datapool web application:

When sentinel.py runs for the first time, datapoolclient.py will create a set of sub-directories. You will need to adjust the client.json file in the newly created settings sub-directory.

Important

The client.json file contains the access details, such as the Datapool web application url, the client_id and client_secret.

These details must match the client registration within the Datapool web application.

Remote client registration within Datapool

You will need to register the new client with one of the Datappol user accounts. To do this, go to 'Admin' → 'Account' and expand 'App credentials' (Lock symbol). Remember the registered client will have the same privileges as the user of this account but limited to the selected scope. The scope for the Raspberry Piclient must be class SourcePot\Datapool\Processing\RemoteClient and the method clientCall. The method clientCall of class SourcePot\Datapool\Processing\RemoteClient will handle the client requests.

The following screenshot shows the registration of the client in row 0001:

Multiple Raspberry Pis can run as clients with the same client_id. The Raspberry Pis are are distinguished by their location and the location of a Raspberry Pi is set by entry={'Group':'Town','Folder':'Address','Name':'Location'} in sentinel.py. Just replace Town, Address and Location with the correct values. When a Raspberry Pi connects for the very first time to the RemoteClient a database entry in the table remotecliwentis creted based on Town, Address and Location. The entry's EntryId is '...definition' and contains the html widget template definitions for status and settings. These are provided by the Raspberry Pi, i.e. the Raspberry Pi's Python script defines the user interface within the Datapool web application. The settings, that control the Raspberry Pi, will be stored in the same table as entry with an EntryId="..._setting". The latest data provided by the Raspberry Pi is saved as entry in the same table with the EntryId="..._lastentry".

Example view on the Datapool web application

The RemoteClient processor provides an user interface which is actually defined by the Python code of the remote client itself. Within the sentinel.py file the Python dictionary entry, key Content||Settings||... defines the control elements and entry key Content||Status||... the status elements (display). This allows each remote client to provide different functionalities and to specify it´s specific control elements (buttons, drop-dwon menus, slider etc.) for the Datapool web application.