Add blogpost about Elasticsearch, Meilisearch and Solr

docs/blog/index.rst

@@ -12,3 +12,4 @@ Blog
    intro-offline
    private-engines
    command-line-engines
+   search-indexer-engines

docs/blog/search-indexer-engines.rst

@@ -0,0 +1,114 @@
+===============================
+Query your local search engines
+===============================
+
+From now on, searx lets you to query your locally running search engines. The following
+ones are supported now:
+
+* `Elasticsearch`_
+* `Meilisearch`_
+* `Solr`_
+
+All of the engines above are added to ``settings.yml`` just commented out, as you have to
+``base_url`` for all them.
+
+Please note that if you are not using HTTPS to access these engines, you have to enable
+HTTP requests by setting ``enable_http`` to ``True``.
+
+Futhermore, if you do not want to expose these engines on a public instance, you can
+still add them and limit the access by setting ``tokens`` as described in the `blog post about
+private engines`_.
+
+Configuring searx for search engines
+====================================
+
+Each search engine is powerful, capable of full-text search.
+
+Elasticsearch
+-------------
+
+Elasticsearch supports numerous ways to query the data it is storing. At the moment
+the engine supports the most popular search methods: ``match``, ``simple_query_string``, ``term`` and ``terms``.
+
+If none of the methods fit your use case, you can select ``custom`` query type and provide the JSON payload
+searx has to submit to Elasticsearch in ``custom_query_json``.
+
+The following is an example configuration for an Elasticsearch instance with authentication
+configured to read from ``my-index`` index.
+
+.. code:: yaml
+
+  - name : elasticsearch
+    shortcut : es
+    engine : elasticsearch
+    base_url : http://localhost:9200
+    username : elastic
+    password : changeme
+    index : my-index
+    query_type : match
+    enable_http : True
+
+
+Meilisearch
+-----------
+
+This search engine is aimed at individuals and small companies. It is designed for
+small-scale (less than 10 million documents) data collections. E.g. it is great for storing
+web pages you have visited and searching in the contents later.
+
+The engine supports faceted search, so you can search in a subset of documents of the collection.
+Futhermore, you can search in Meilisearch instances that require authentication by setting ``auth_token``.
+
+Here is a simple example to query a Meilisearch instance:
+
+.. code:: yaml
+
+  - name : meilisearch
+    engine : meilisearch
+    shortcut: mes
+    base_url : http://localhost:7700
+    index : my-index
+    enable_http: True
+
+
+Solr
+----
+
+Solr is a popular search engine based on Lucene, just like Elasticsearch.
+But instead of searching in indices, you can search in collections.
+
+This is an example configuration for searching in the collection ``my-collection`` and get
+the results in ascending order.
+
+.. code:: yaml
+
+  - name : solr
+    engine : solr
+    shortcut : slr
+    base_url : http://localhost:8983
+    collection : my-collection
+    sort : asc
+    enable_http : True
+
+
+Next steps
+==========
+
+The next step is to add support for various SQL databases.
+
+Acknowledgement
+===============
+
+This development was sponsored by `Search and Discovery Fund`_ of `NLnet Foundation`_ .
+
+.. _blog post about private engines: private-engines.html#private-engines
+.. _Elasticsearch: https://www.elastic.co/elasticsearch/
+.. _Meilisearch: https://www.meilisearch.com/
+.. _Solr: https://solr.apache.org/
+.. _Search and Discovery Fund: https://nlnet.nl/discovery
+.. _NLnet Foundation: https://nlnet.nl/
+
+
+| Happy hacking.
+| kvch // 2021.04.07 23:16
+