Context

As part of the transition to WEkEO 2.0, the Harmonized Data Access (HDA) also has undergone a significant evolution. The most significant changes to the API are:

Synchronous jobs for search and download
Faster search results with pagination
Simplified syntax of the search request

Let's dive deeper into the new HDA improvements and see the changes to consider! 💪

Improvements of new HDA

One of the main enhancements of the new HDA is the simplified query syntax.

Here is a comparison between old and new HDA query:

Old HDA request syntax (click me)

{
"datasetld": "EO:EUM:DAT:METOP:GLB-SST-NC",
"dateRangeSelectValues": [
  {
    "name":"position",
     "start":"2016-07-11T05:58:00.000Z",
     "end":"2016-07-12T00:00.000Z",
  }
],
"stringChoiceValues":[
  {
    "name":"sat",
    "value":"Metop-B"
  },
  {
    "name":"type",
    "value":"OSSTGLBN"
  }
]
}

New HDA request syntax (click me)

{
"dataset_id": "EO:EUM:DAT:METOP:GLB-SST-NC",
"dtstart": "2016-07-11T00:00:00.000Z",
"dtend": "2016-07-12T00:00:00.000Z",
"sat": "Metop-B",
"type": "OSSTGLBN"
}

We clearly see the difference, the new HDA query is a lot more compact and easy to build and read.

Then, the new HDA API is made more user-friendly and simplifies the process of searching and downloading through the use of the hda Python library.

Also the CliMetLab plugin from WEkEO simplifies the process of downloading data and working with various data formats for users, while also providing a more user-friendly way to display data.

Changes to apply with new HDA

There are a few changes to take into consideration with the new version of the HDA:

You should convert your queries from old to new syntax as the example given in previous section. For the moment, old syntax is still working for transition purpose.
You must delete the URL in your existing .hdarc file if it still contains it. Otherwise, you will encounter an error with the new version of the HDA.
When using the HDA REST API, you need to run the following commands to obtain or refresh a token (a token has to be refreshed every hour):
- Command curl to request a token:
```
curl -X POST -H 'Content-Type: application/json' -d '{"username":"USERNAME","password":"PASSWORD"}' https://gateway.prod.wekeo2.eu/hda-broker/gettoken
```
  where USERNAME and PASSWORD must be replaced with your WEkEO credentials.
  This is how you can retrieve your access token:
```
{"access_token":"29020185-xxxx-xxxx-xxxx-78626d0xxxx", [...]}
```
- Command curl to refresh a token:
```
curl -d "refresh_token=REFRESH_TOKEN" https://gateway.prod.wekeo2.eu/hda-broker/refreshtoken
```
  where the REFRESH_TOKEN is provided by the first call of gettoken like this:
```
{"access_token":"xxxxxx","refresh_token":"xxxxx", [...]}
```

Complete example to create and refresh a token (click me)

Request a token (replace USERNAME and PASSWORD with your WEkEO credentials):

curl -X POST -H 'Content-Type: application/json' -d '{"username":"USERNAME","password":"PASSWORD"}' https://gateway.prod.wekeo2.eu/hda-broker/gettoken

Return:

{"access_token":"52ae8f0d-1bbf-3f3b-a9b1-f610faba521a",
"refresh_token":"ecd1886e-b7ed-3e1c-9aa9-76bc2df9e494",
"scope":....,
"expires_in":3600}

Refresh the token:

curl -d "refresh_token=ecd1886e-b7ed-3e1c-9aa9-76bc2df9e494" https://gateway.prod.wekeo2.eu/hda-broker/refreshtoken

Return

{"access_token":"662d58a3-200d-3dca-a51c-05cfad23f350",
"refresh_token":"e2077f52-3fe9-3660-8cee-f2a9acb6c64b",
"scope":....,
"expires_in":3600}

This command gives you a new token valid for 1 hour.

💡 WEkEO Pro Tip: you can visit the HDA Broker containing detailed information on the HDA features, with short descriptions and test functionality.

What's next?

We are user-driven and we implement users' suggestions, so feel free to contact us:

through a chat session available in the bottom right corner of the page
via our contact webpage
via e-mail to our support team (supportATwekeo.eu)

Regardless of how you choose to contact us, you will first be put in touch with our AI Agent Neo. At any time, you can reach a member of the WEkEO User Support team by clicking on "talk to a person" via chat, or by naturally requesting it in reply to Neo's email.

How to download WEkEO data?

HDA API errors

How to use the HDA API in Python?

How to use the Harmonized Data Access REST API with cURL?

What is the Harmonized Data Access (HDA) API?