jobliz/tag_search_with_elasticsearch_6.md

## tag_search_with_elasticsearch_6.md

      
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              tag_search_with_elasticsearch_6.md
            
          
    Tag Search with ElasticSearch 6

This is a modified version of
this tutorial,
the queries have been modified so that they work with ES6. Many backwards incompatible changes happened between
previous verions and 6, so many how-to's on the internet are outdated. If you're just starting learning ElasticSearch
with version 6 then you should read these links and keep a mental note of them.


CURL syntax with ElasticSearch:
CURL calls need to be done in a certain manner for them to work correctly. There are situations in which ElasticSearch
does not complain but the search or query is not processed correctly. Check your CURL call if it ever complains
about globbing.


Removal of the string type:
Per the blog: The string field has split into two new types: text, which should be used for full-text search,
and keyword, which should be used for keyword search.


Removal of mapping types:
The developers have good technical arguments,
for this, so if you're just learning with ElasticSearch 6 there's nothing you can do but adapt.


Keyword type and not_analyzed:
The "keyword" type does not seem to need the "not_analyzed" parameter.


'no query registered for filtered' error
The filtered query has been deprecated and removed in ES 5.0. You should now use the bool/must/filter query instead.


Now with all this and the
Query DSL
in mind, let's create the index:
curl -H 'Content-Type: application/json' -X PUT 'http://localhost:9200/movies/' -d '
{
    "settings" : {
        "number_of_shards" : 1
    },
    "mappings" : {
        "movie": {
            "properties": {
                "director": {
                    "type": "text"
                },
                "genres": {
                    "type": "keyword"
                },
                "title": {
                    "type": "text"
                },
                "year": {
                    "type": "long"
                }
            }
        }
    }
}'

You can delete the index with:
curl -XDELETE 'http://localhost:9200/movies/'

Posting documents to the index:
curl -H 'Content-Type: application/json' -X POST 'http://localhost:9200/movies/movie' -d '
{
    "title": "Apocalypse Now",
    "director": "Francis Ford Coppola",
    "year": 1979,
    "genres": ["Drama", "War", "Foo"]
}'

curl -H 'Content-Type: application/json' -X POST 'http://localhost:9200/movies/movie' -d '
{
    "title": "Apocalypse Now",
    "director": "Francis Ford Coppola",
    "year": 1979,
    "genres": ["Drama", "War", "Foo", "Bar"]
}'

curl -H 'Content-Type: application/json' -X POST 'http://localhost:9200/movies/movie' -d '
{
    "title": "Apocalypse Now",
    "director": "Francis Ford Coppola",
    "year": 1979,
    "genres": ["Drama", "Bar"]
}'

Let's see what got in. This should produce the three items we just posted.
curl -XGET 'localhost:9200/movies/movie/_search?pretty' '{}'

The first tag search:
GET movies/movie/_search

curl -H 'Content-Type: application/json' -XPOST 'localhost:9200/movies/movie/_search?pretty' -d '
{
    "query": {
        "bool": {
            "filter": {
                "terms": {
                    "genres": ["War", "Foo"]
                }
            }
        }
    }
}'

The second tag search, excluding one tag:
curl -H 'Content-Type: application/json' -XPOST 'localhost:9200/movies/movie/_search?pretty' -d '
{
    "query": {
        "bool": {
            "must": [
                { "match": { "genres": "War" } },
                { "match": { "genres": "Foo" } },
                { "match": { "genres": "Drama" } }
            ],
            "must_not": [
                { "match": { "genres": "Bar" } }
            ]
        }
    }
}'