Class: Moneta::Adapters::Couch
- Inherits:
-
Object
- Object
- Moneta::Adapters::Couch
- Includes:
- Defaults
- Defined in:
- lib/moneta/adapters/couch.rb
Overview
CouchDB backend
You can store hashes directly using this adapter.
Instance Attribute Summary collapse
- #backend ⇒ Object readonly
Instance Method Summary collapse
-
#clear(options = {}) ⇒ void
Clear all keys in this store.
-
#create(key, value, options = {}) ⇒ Boolean
Atomically sets a key to value if it’s not set.
-
#delete(key, options = {}) ⇒ Object
Delete the key from the store and return the current value.
-
#each_key ⇒ Object
Calls block once for each key in store, passing the key as a parameter.
-
#initialize(options = {}) ⇒ Couch
constructor
A new instance of Couch.
-
#key?(key, options = {}) ⇒ Boolean
Exists the value with key.
-
#load(key, options = {}) ⇒ Object
Fetch value with key.
-
#merge!(pairs, options = {}) ⇒ Object
Stores the pairs in the key-value store, and returns itself.
-
#slice(*keys, **options) ⇒ <(Object, Object)>
Returns a collection of key-value pairs corresponding to those supplied keys which are present in the key-value store, and their associated values.
-
#store(key, value, options = {}) ⇒ Object
Store value with key.
-
#values_at(*keys, **options) ⇒ Array<Object, nil>
Returns an array containing the values associated with the given keys, in the same order as the supplied keys.
Methods included from Defaults
#[], #[]=, #close, #decrement, #features, #fetch, #fetch_values, included, #increment, #supports?, #update
Methods included from OptionSupport
#expires, #prefix, #raw, #with
Constructor Details
#initialize(options = {}) ⇒ Couch
Returns a new instance of Couch.
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# File 'lib/moneta/adapters/couch.rb', line 30 def initialize( = {}) @value_field = [:value_field] || 'value' @type_field = [:type_field] || 'type' url = "http://#{[:host] || '127.0.0.1'}:#{[:port] || 5984}/#{[:db] || 'moneta'}" @backend = [:backend] || ::Faraday.new(url: url) @rev_cache = Moneta.build do use :Lock adapter :LRUHash end create_db end |
Instance Attribute Details
#backend ⇒ Object (readonly)
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# File 'lib/moneta/adapters/couch.rb', line 19 def backend @backend end |
Instance Method Details
#clear(options = {}) ⇒ void
This method returns an undefined value.
Clear all keys in this store
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# File 'lib/moneta/adapters/couch.rb', line 85 def clear( = {}) @backend.delete '' create_db self end |
#create(key, value, options = {}) ⇒ Boolean
Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.
Atomically sets a key to value if it’s not set.
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# File 'lib/moneta/adapters/couch.rb', line 92 def create(key, value, = {}) body = value_to_body(value, nil) response = @backend.put(key, body, 'Content-Type' => 'application/json') update_rev_cache(key, response) case response.status when 201 true when 409 false else raise "HTTP error #{response.status}" end rescue tries ||= 0 (tries += 1) < 10 ? retry : raise end |
#delete(key, options = {}) ⇒ Object
Delete the key from the store and return the current value
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# File 'lib/moneta/adapters/couch.rb', line 69 def delete(key, = {}) clear_rev_cache(key) get_response = @backend.get(key) if get_response.status == 200 existing_rev = get_response['etag'][1..-2] value = body_to_value(get_response.body) delete_response = @backend.delete("#{key}?rev=#{existing_rev}") raise "HTTP error #{response.status}" unless delete_response.status == 200 value end rescue tries ||= 0 (tries += 1) < 10 ? retry : raise end |
#each_key ⇒ Enumerator #each_key {|key| ... } ⇒ self
Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.
Calls block once for each key in store, passing the key as a parameter. If no block is given, an enumerator is returned instead.
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# File 'lib/moneta/adapters/couch.rb', line 110 def each_key return enum_for(:each_key) unless block_given? skip = 0 limit = 1000 total_rows = 1 while total_rows > skip do response = @backend.get("_all_docs?" + encode_query(limit: limit, skip: skip)) case response.status when 200 result = MultiJson.load(response.body) total_rows = result['total_rows'] skip += result['rows'].length result['rows'].each do |row| key = row['id'] @rev_cache[key] = row['value']['rev'] yield key end else raise "HTTP error #{response.status}" end end self end |
#key?(key, options = {}) ⇒ Boolean
Exists the value with key
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# File 'lib/moneta/adapters/couch.rb', line 43 def key?(key, = {}) response = @backend.head(key) update_rev_cache(key, response) response.status == 200 end |
#load(key, options = {}) ⇒ Object
Fetch value with key. Return nil if the key doesn’t exist
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# File 'lib/moneta/adapters/couch.rb', line 50 def load(key, = {}) response = @backend.get(key) update_rev_cache(key, response) response.status == 200 ? body_to_value(response.body) : nil end |
#merge!(pairs, options = {}) ⇒ self #merge!(pairs, options = {}) {|key, old_value, new_value| ... } ⇒ self
Stores the pairs in the key-value store, and returns itself. When a block is provided, it will be called before overwriting any existing values with the key, old value and supplied value, and the return value of the block will be used in place of the supplied value.
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# File 'lib/moneta/adapters/couch.rb', line 153 def merge!(pairs, = {}) keys = pairs.map { |key, _| key }.to_a cache_revs(*keys.reject { |key| @rev_cache[key] }) if block_given? existing = Hash[slice(*keys, **)] pairs = pairs.map do |key, new_value| [ key, if existing.key?(key) yield(key, existing[key], new_value) else new_value end ] end end docs = pairs.map { |key, value| value_to_doc(value, @rev_cache[key], key) }.to_a body = MultiJson.dump(docs: docs) response = @backend.post('_bulk_docs', body, "Content-Type" => "application/json") raise "HTTP error #{response.status}" unless response.status == 201 retries = [] MultiJson.load(response.body).each do |row| if row['ok'] == true @rev_cache[row['id']] = row['rev'] elsif row['error'] == 'conflict' clear_rev_cache(row['id']) retries << pairs.find { |key, _| key == row['id'] } else raise "Unrecognised response: #{row}" end end # Recursive call with all conflicts if retries.empty? self else merge!(retries, ) end end |
#slice(*keys, **options) ⇒ <(Object, Object)>
The keys in the return value may be the same objects that were supplied (i.e. Object#equal?), or may simply be equal (i.e. Object#==).
Some adapters may implement this method atomically. The default implmentation uses #values_at.
Returns a collection of key-value pairs corresponding to those supplied keys which are present in the key-value store, and their associated values. Only those keys present in the store will have pairs in the return value. The return value can be any enumerable object that yields pairs, so it could be a hash, but needn’t be.
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# File 'lib/moneta/adapters/couch.rb', line 142 def slice(*keys, **) response = @backend.get('_all_docs?' + encode_query(keys: keys, include_docs: true)) raise "HTTP error #{response.status}" unless response.status == 200 docs = MultiJson.load(response.body) docs["rows"].map do |row| next unless row['doc'] [row['id'], doc_to_value(row['doc'])] end.compact end |
#store(key, value, options = {}) ⇒ Object
Store value with key
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# File 'lib/moneta/adapters/couch.rb', line 57 def store(key, value, = {}) body = value_to_body(value, rev(key)) response = @backend.put(key, body, 'Content-Type' => 'application/json') update_rev_cache(key, response) raise "HTTP error #{response.status} (PUT /#{key})" unless response.status == 201 value rescue tries ||= 0 (tries += 1) < 10 ? retry : raise end |
#values_at(*keys, **options) ⇒ Array<Object, nil>
Some adapters may implement this method atomically, but the default implementation simply makes repeated calls to #load.
Returns an array containing the values associated with the given keys, in the same order as the supplied keys. If a key is not present in the key-value-store, nil is returned in its place.
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# File 'lib/moneta/adapters/couch.rb', line 136 def values_at(*keys, **) hash = Hash[slice(*keys, **)] keys.map { |key| hash[key] } end |