Filter using HBase REST API

Question

Does anyone know anything about the HBase REST API? Im currently writing a program which inserts and reads from HBase using curl commands. When trying to read I use the curl get command, e.g.

curl -X GET 'http://server:9090/test/Row-1/Action:ActionType/' -h 'Accept:application/json'

This returns the column Action:ActionType from Row-1. If I want to do the equivalent of a WHERE clause using the GET command I am stuck however. Im not sure its even possible? If I want to find all records where Action:ActionType =1 for example. Help is appreciated!

Answer 1

You can do this by using a filter (here a SingleColumnValueFilter) in your CURL request.

First, create a XML file (myscanner.xml) describing your scan. Here we want to filter according to a qualifier value, with EQUAL operator) :

<Scanner batch="10">
    <filter>
        {
            "type": "SingleColumnValueFilter",
            "op": "EQUAL",
            "family": "<FAMILY_BASE64>",
            "qualifier": "<QUALIFIER_BASE64>",
            "latestVersion": true,
            "comparator": {
                "type": "BinaryComparator",
                "value": "<SEARCHED_VALUE_BASE64>"
            }
        }
    </filter>
</Scanner>

You should replace <FAMILY_BASE64>, <QUALIFIER_BASE64> and <SEARCHED_VALUE_BASE64> with your own values (values must be converted to base64, you can do echo -en ${FAMILY} | base64.

Then, submit a CURL request to HBase REST API with this XML file as data :

curl -vi -X PUT \
    -H "Content-Type:text/xml" \
    -d @myscanner.xml \
    "http://${HOST}:${REST_API_PORT}/${TABLE_NAME}/scanner/"

This request should return a Scanner object, like :

[...]
Location: http://${HOST}:${REST_API_PORT}/${TABLE_NAME}/scanner/149123344543470bea57a

Then use the given scanner to iterate through results (request multiple times to iterate) :

curl -vi -X GET \
    -H "Accept: text/xml" \
    "http://${HOST}:${REST_API_PORT}/${TABLE_NAME}/scanner/149123344543470bea57a"

You can also accept "application/json" instead of XML. Notice that the results are base64 encoded.

Sources :

HBase REST Filter ( SingleColumnValueFilter )

A list of filters you can use : https://gist.github.com/stelcheck/3979381

Cloudera documentation about HBase REST API : https://www.cloudera.com/documentation/enterprise/5-9-x/topics/admin_hbase_rest_api.html