clojure-solr

Clojure bindings for Apache Solr.

Installation

To use within a Leiningen project, add the following to your project.clj file:

[cc.artifice/clojure-solr "2.0.0"]

To build from source, run:

lein deps
lein jar

Usage

• Basic usage

  (with-connection (connect "http://127.0.0.1:8983/solr")
    (add-document! {"id" "testdoc", "name" "A Test Document"})
    (add-documents! [{"id" "testdoc.2", "name" "Another test"}
                             {"id" "testdoc.3", "name" "a final test"}])
    (commit!)
    (search "test")
    (search "test" :rows 2))
  

• Advanced Usage

  • Parameters can be passed as a map, that contains Solr parameter names as keywords e.g (start, fields, facet-filters, etc..)

  Optional keys, passed in a map:
  :method :get or :post (default :get)
  :rows Number of rows to return (default is Solr default: 1000)
  :start Offset into query result at which to start returning rows (default 0)
  :fields Fields to return
  :facet-fields Discrete-valued fields to facet.  Can be a string, keyword, or map containing {:name ... :prefix ...}.
  :facet-queries Vector of facet queries, each encoded in a string or a map of {:name, :value, :formatter}.  :formatter is optional and defaults to the raw query formatter. The result is in the :facet-queries response.
  :facet-date-ranges Date fields to facet as a vector or maps.  Each map contains
  :field Field name
  :tag Optional, for referencing in a pivot facet
  :start Earliest date (as java.util.Date)
  :end Latest date (as java.util.Date)
  :gap Faceting gap, as String, per Solr (+1HOUR, etc)
  :others  Comma-separated string: before,after,between,none,all.  Optional.
  :include Comma-separated string: lower,upper,edge,outer,all.  Optional.
  :hardend Boolean (See Solr doc).  Optional.
  :missing Boolean--return empty buckets if true.  Optional.
  :facet-numeric-ranges Numeric fields to facet, as a vector of maps.  Map fields as for date ranges, but start, end and gap must be numbers.
  :facet-mincount Minimum number of docs in a facet for the bucket to be returned.
  :facet-hier-sep Useful for path hierarchy token faceting.  A regex, such as \\|.
  :facet-filters Solr filter expression on facet values.  Passed as a map in the form: {:name 'facet-name' :value 'facet-value' :formatter (fn [name value] ...) } where :formatter is optional and is used to format the query.
  :facet-pivot-fields Vector of pivots to compute, each a list of facet fields. If a facet is tagged (e.g., {:tag ts} in :facet-date-ranges) then the string should be {!range=ts}other-facet.  Otherwise, use comma separated lists: this-facet,other-facet.
  

  (with-connection...
    (search "query" {:rows 10, :start 0 :fields <vector-of-fieldnames> :facet-filters {:name "facet-name" :value "facet-value" :formatter (fn...)})
    ;; formatter is optional and used to format the query.
  

• Optionally use a connection manager

  • (hint: Use PoolingHttpClientConnectionManager when clojure-solr is used in a web server to query Solr in a multithreaded environment, to avoid creating thousands of dangling CLOSE_WAIT sockets.)

  (with-connection (connect <url> <connection-manager>)
  ;; connection operations...
  

• Atomically update a document.

  doc: can be a document previously fetched from solr or the id of such a document
  unique-key: Name of the attribute that is the document's unique key.
  changes: a vector of maps containg :attribute, :func (:set, :inc, :add) and :value.
  

  (atomically-update! doc \"some-key"\ [{:attribute :client :func :set :value \"some-client-value\"}])
  

• Debug queries

  trace function: a function to "debug" query
  body: query operation.
  

  (with-trace (fn [str] (debug [str]))
    (with-connection...
      (search... )))
  

• More Like this

  Execute a Solr moreLikeThis (mlt) query.
  id: unique id of doc to match.
  unique-key: Name of key in schema that corresponds to id.
  similarity-fields: Fields to match against.  Pass as comma-separated list or vector.
  params: Map of optional parameters:
    match-include? -- this is not clearly documented.  See Solr manual.
    min-doc-freq -- ignore words that don't occur in at least this many docs.  Default 3.
    min-term-freq -- ignore terms that occur fewer times than this in a document. Default 2.
    min-word-len -- minimum word length for matching.  Default 5.
    boost? -- Specifies if query will be boosted by interesting term relevance.  Default true.
    max-query-terms -- Maximum number of query terms in a search.  Default 1000.
    max-results -- Maximum number of similar docs returned.  Default 5.
    fields -- fields of docs to return.  Pass as vector or comma-separated list..  Default: unique key + score.
    method -- Solr Query method
  

  (more-like-this doc-id doc-id-name [fields..] {:min-doc-freq 4 :min-word-len 6 :max-results 10 ...})