# Accessing Data from External Clients (QGIS)

## Install QGIS Desktop

- Open the `Ubuntu Software` app

    ![image](img/136914738-bcf7ebc2-6420-47c2-b876-f982945f0f56.png)

- Click `CTRL + F` and search for `qgis`, click on the `QGIS Desktop` icon

    ![image](img/136914846-95358fc2-aa9b-4a4d-92f2-ab2e2548e484.png)

- Click on `INSTALL` and wait for the process to finish

    ![image](img/136915019-bb082b2e-4372-4d4d-b8cd-614b32e0ac50.png)

- Once the app has been installed, open it by clicking on the icon

    ![image](img/136915075-6496ba07-3af7-45b1-9cdc-2d93530a0920.png)

## Connect through BASIC Auth
This is the easiest way to connect the client to GeoNode:

    - Pros: very easy to configure
    - Cons: it always uses a fixed user and you need to change it anytime if you want to switch user

- Let's add a `VECTORIAL` layer accessible to `test_user1` to the client. Click on `Layer > Add Layer > Add WFS Layer...`

    ![image](img/136917776-624696aa-c345-43d8-a117-f9e9bcc49b67.png)

- Create a `New Connection`

    ![image](img/136917846-a27e5109-eede-44ef-b695-7e0e8f990e56.png)

- Provide a name, e.g. `GeoNode WFS`, and the following URL:

    - `http://localhost/gs/ows`
    
    ![image](img/136918114-c9bd2c31-75d0-46cd-abae-5f6f48098fb8.png)

    _IMPORTANT: It is mandatory to pass through the GeoNode proxy_ `/gs/` _instead of hitting the GeoServer endpoint directly_

- If the client asks for a `NEW master password` you can provide any one (e.g. `geonode`)

    ![image](img/136918608-ce4f5b10-433a-43e4-8b2f-68b3f005865d.png)

- Switch to `Basic` authentication, provide the `test_user1` credentials, and click on `Convert to configuration`

    ![image](img/136922761-ff3890b1-7781-4ce9-986f-8cfe11c553bf.png)

- Make sure the converted configuration is selected and click on `Detect` to verify that it works. Click on `OK` when finished

    ![image](img/136918990-c2d355c6-94e1-4a32-b126-986b40549327.png)

## Connect through OAuth2
This is the easiest way to connect the client to GeoNode:

    - Pros: it redirects to GeoNode to authenticate, so you can use any login provided by GeoNode
    - Cons: difficult to configure

- We need to prepare GeoNode first, as an `admin` go to the `Admin Dashboard` and look for `Django OAuth Toolkit > Applications`

    ![image](img/136919833-371ebe26-03fc-4f96-bd8a-3cb304493361.png)

- Edit the `GeoServer` one

    ![image](img/136919931-53a0ee34-4687-4281-a422-c4cfe2c7cccf.png)

- Add the following URL to the `Redirect URIs` section and take note of the `Client ID` and `Client Secret` keys:

    * **Copy the Client ID / Client Secret**

    ![image](img/136920356-99b64556-6bf7-440b-99dd-0c1e9f3d4014.png)

    * **Add Redirect URIs and Save**: `http://127.0.0.1:7070/qgis-client`

    ![image](img/136920406-53eb70a3-d2ae-4ed9-b108-20be60c29223.png)


- Let's add a `VECTORIAL` layer accessible to `test_user1` to the client. Click on `Layer > Add Layer > Add WFS Layer...`

    ![image](img/136917776-624696aa-c345-43d8-a117-f9e9bcc49b67.png)

- Add a new `OAuth2 Authentication` config and fill the fields as follows:

    * **Name**: _Provide any name you want, e.g._ `GeoNode OAuth2`
    * **Grant Flow**: `Authorization Code`
    * **Request URL**: `http://localhost/o/authorize/`   (**the** `/` **at the end is IMPORTANT!**)
    * **Token URL**: `http://localhost/o/token/`   (**the** `/` **at the end is IMPORTANT!**)
    * **Refresh token URL**: `http://localhost/o/token/`   (**the** `/` **at the end is IMPORTANT!**)
    * **Client ID / Client Secret**: _The ones above_
    * **Scope**: `openid write`
    * **Token session**: `True`
    * **Access method**: `Header`
    * **Token header**: _empty_  (**it is important you leave this parameter empty*)*
    * **Save**
    
    ![image](img/136948695-5310e7fb-9bac-46c7-a32d-2843be89041c.png)

- Make sure the new configuration is selected, and click on `Detect` to verify that it works. Click on `OK` when finished

    ![image](img/136923742-a0fa4b95-bc66-4f2c-97af-f1bd6efc53d5.png)
    
- The client will automatically open a browser session. If you are not logged in, sign in with `admin` (or whatever user you want).

- The window below means that the authentication process was successful. You can safely close it and go back to the client

    ![image](img/136923358-3b54e963-49b2-4e78-9bcd-2fb4512a7c9d.png)

### Throubleshooting: if the QGIS client does not correctly redirect to the browser

- Check that the `Default Application` for the `WEB` is set to `Firefox`

    ![image](img/qgis_tshoot_001.png)

- If this is not the case, open a `Terminal` window and run the following command lines:

    ```shell
    sudo apt update
    sudo apt install firefox
    ```

- Close the `Firefox` windows and try again.

### Throubleshooting: if the QGIS client returns a redirect uri error code

- In the case you get an error like this

    ![image](img/qgis_tshoot_002.png)

- Check the `URL` on the browser location bar and make sure the `redirect_uri` is set to `http://127.0.0.1:7070/qgis-client`; if not, change it **manually** and refresh!

- This should be also added to the GeoNode `Oauth2` application.

## Attach Layer to the Project

- Once the connection has been configured and saved, whatever it is, go back to the `WFS` panel, select the connection you just created and click on `Connect`

    ![image](img/136935422-d297ae37-b25b-4401-a796-bb1ba1bb29f5.png)

- If everything goes well, you should be able to see the server offering. It will list all the layers the user has access to

    ![image](img/136935553-b5db6117-bcc5-4d14-b48e-33bc6f87118f.png)

- Select the `Test Layer`, and click on `Add`

    ![image](img/136935660-1c67970b-ddcb-40c4-a10c-593cf098b98b.png)

- QGIS will create a new project with the layer already loaded and centered on the map

    ![image](img/136950197-9430ba5e-008a-410d-abf3-6f797c08d892.png)

## Editing Contents: Values

- Enable `Editing Mode` on QGIS, and click on the `Info` button

    ![image](img/136950557-79ebfe19-42e7-4bc2-a570-e3284d3bce33.png)
    
- Click over the geometry to edit, and on the right-hand panel, expand and click on the link `Edit feature form`

    ![image](img/136950920-6a177c0e-58fa-4229-8852-0e7b20c95e56.png)

- That will show a small form with the values, change a few of them, and click on the `OK` button

    ![image](img/136951126-0761cac6-7ba5-4517-bcbf-5b7c2ad976f9.png)

- A small `floppy disk` button will enable near the editing one meaning that there are some pending changes to be committed to the server. Click on it in order to persist the changes

    ![image](img/136951347-2b405b41-6f09-49cf-9e2e-3d56b3b6585a.png)

- After a successful commit, the `floppy disk` button will be disabled again

## Editing Contents: Geometries

- Enable `Editing Mode` on QGIS and click on the `Info` button

    ![image](img/136950557-79ebfe19-42e7-4bc2-a570-e3284d3bce33.png)

- Click on the `Vertex Tool` and enable it. From now on, you will be able to modify a geometry's vertices by moving over it 

    ![image](img/136952225-3827b983-f192-4285-a80a-facc85af2d33.png)

- Once happy with the changes, save them as we have done previously with the values

    ![image](img/136952375-5fe8775a-f7da-4455-b2f8-6dfe7ba2bb57.png)

- With this specific layer, you will most probably get an error on the bounding box extension. This is caused by the native projection of the layer, and QGIS not being able to correctly manage the `dateline`

    ![image](img/136952674-ef76f8f3-1b0b-4a9d-a8fc-00832599ea11.png)

- It is still possible to edit the layer from GeoNode directly. However, to fix this issue easily, we will convert the layer into a `Mercator Projected` one.

We will pass it through the database to perform such an operation. In the next section, we will see how to re-project and store a DB table in a layer and then push it back to GeoNode.
    
#### [Next Section: Advanced layers publishing and management](ADV_LAYERS_PUB.md)