Class: Sova::Database

Inherits:
Object
  • Object
show all
Defined in:
lib/sova/database.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(server, name) ⇒ Database

Create a Sova::Database adapter for the supplied Sova::Server and database name.

Parameters

server<Sova::Server>

database host

name<String>

database name



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# File 'lib/sova/database.rb', line 16

def initialize(server, name)
  @name = name
  @server = server
  @host = server.uri
  @uri  = "/#{name.gsub('/','%2F')}"
  @root = host + uri
  @bulk_save_cache = []
  @bulk_save_cache_limit = 500  # must be smaller than the uuid count
end

Instance Attribute Details

#bulk_save_cache_limit ⇒ Object

Returns the value of attribute bulk_save_cache_limit.



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# File 'lib/sova/database.rb', line 7

def bulk_save_cache_limit
  @bulk_save_cache_limit
end

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/sova/database.rb', line 6

def host
  @host
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/sova/database.rb', line 6

def name
  @name
end

#root ⇒ Object (readonly)

Returns the value of attribute root.



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# File 'lib/sova/database.rb', line 6

def root
  @root
end

#server ⇒ Object (readonly)

Returns the value of attribute server.



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# File 'lib/sova/database.rb', line 6

def server
  @server
end

#uri ⇒ Object (readonly)

Returns the value of attribute uri.



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# File 'lib/sova/database.rb', line 6

def uri
  @uri
end

Instance Method Details

#batch_save_doc(doc) ⇒ Object

Save a document to CouchDB in batch mode. See #save_doc’s batch argument.



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# File 'lib/sova/database.rb', line 185

def batch_save_doc(doc)
  save_doc(doc, false, true)
end

#bulk_save(docs = nil, use_uuids = true) ⇒ Object Also known as: bulk_delete

POST an array of documents to CouchDB. If any of the documents are missing ids, supply one from the uuid cache.

If called with no arguments, bulk saves the cache of documents to be bulk saved.



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# File 'lib/sova/database.rb', line 193

def bulk_save(docs = nil, use_uuids = true)
  if docs.nil?
    docs = @bulk_save_cache
    @bulk_save_cache = []
  end
  if (use_uuids) 
    ids, noids = docs.partition{|d|d['_id']}
    uuid_count = [noids.length, @server.uuid_batch_count].max
    noids.each do |doc|
      nextid = @server.next_uuid(uuid_count) rescue nil
      doc['_id'] = nextid if nextid
    end
  end
  HTTP.post "#{@root}/_bulk_docs", {:docs => docs}
end

#bulk_save_doc(doc) ⇒ Object

Save a document to CouchDB in bulk mode. See #save_doc’s bulk argument.



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# File 'lib/sova/database.rb', line 180

def bulk_save_doc(doc)
  save_doc(doc, true)
end

#compact! ⇒ Object

Compact the database, removing old document revisions and optimizing space use.



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# File 'lib/sova/database.rb', line 264

def compact!
  HTTP.post "#{@root}/_compact"
end

#copy_doc(doc, dest) ⇒ Object

COPY an existing document to a new id. If the destination id currently exists, a rev must be provided. dest can take one of two forms if overwriting: “id_to_overwrite?rev=revision” or the actual doc hash with a ‘_rev’ key

Raises:

  • (ArgumentError) 


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# File 'lib/sova/database.rb', line 229

def copy_doc(doc, dest)
  raise ArgumentError, "_id is required for copying" unless doc['_id']
  slug = escape_docid(doc['_id'])        
  destination = if dest.respond_to?(:has_key?) && dest['_id'] && dest['_rev']
    "#{dest['_id']}?rev=#{dest['_rev']}"
  else
    dest
  end
  HTTP.copy "#{@root}/#{slug}", destination
end

#create! ⇒ Object

Create the database



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# File 'lib/sova/database.rb', line 269

def create!
  bool = server.create_db(@name) rescue false
  bool && true
end

#delete! ⇒ Object

DELETE the database itself. This is not undoable and could be rather catastrophic. Use with care!



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# File 'lib/sova/database.rb', line 295

def delete!
  HTTP.delete @root
end

#delete_attachment(doc, name, force = false) ⇒ Object

DELETE an attachment directly from CouchDB



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# File 'lib/sova/database.rb', line 103

def delete_attachment(doc, name, force=false)
  uri = url_for_attachment(doc, name)
  # this needs a rev
  begin
    HTTP.delete(uri)
  rescue Exception => error
    if force
      # get over a 409
      doc = get(doc['_id'])
      uri = url_for_attachment(doc, name)
      HTTP.delete(uri)
    else
      raise error
    end
  end
end

#delete_doc(doc, bulk = false) ⇒ Object

DELETE the document from CouchDB that has the given _id and _rev.

If bulk is true (false by default) the deletion is recorded for bulk-saving (bulk-deletion :) later. Bulk saving happens automatically when #bulk_save_cache limit is exceded, or on the next non bulk save.

Raises:

  • (ArgumentError) 


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# File 'lib/sova/database.rb', line 215

def delete_doc(doc, bulk = false)
  raise ArgumentError, "_id and _rev required for deleting" unless doc['_id'] && doc['_rev']      
  if bulk
    @bulk_save_cache << { '_id' => doc['_id'], '_rev' => doc['_rev'], '_deleted' => true }
    return bulk_save if @bulk_save_cache.length >= @bulk_save_cache_limit
    return { "ok" => true } # Mimic the non-deferred version
  end
  slug = escape_docid(doc['_id'])        
  HTTP.delete "#{@root}/#{slug}?rev=#{doc['_rev']}"
end

#documents(params = {}) ⇒ Object

Query the _all_docs view. Accepts all the same arguments as view.



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# File 'lib/sova/database.rb', line 37

def documents(params = {})
  keys = params.delete(:keys)
  url = Sova.paramify_url "#{@root}/_all_docs", params
  if keys
    HTTP.post(url, {:keys => keys})
  else
    HTTP.get url
  end
end

#fetch_attachment(doc, name) ⇒ Object

GET an attachment directly from CouchDB



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# File 'lib/sova/database.rb', line 89

def fetch_attachment(doc, name)
  uri = url_for_attachment(doc, name)
  HTTP.request(:get, uri).body
end

#get(id, params = {}) ⇒ Object

GET a document from CouchDB, by id. Returns a Ruby Hash.



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# File 'lib/sova/database.rb', line 82

def get(id, params = {})
  slug = escape_docid(id)
  url = Sova.paramify_url("#{@root}/#{slug}", params)
  result = HTTP.get(url)
end

#get_bulk(ids) ⇒ Object Also known as: bulk_load

load a set of documents by passing an array of ids



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# File 'lib/sova/database.rb', line 48

def get_bulk(ids)
  documents(:keys => ids, :include_docs => true)
end

#info ⇒ Object

GET the database info from CouchDB



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# File 'lib/sova/database.rb', line 32

def info
  HTTP.get @root
end

#put_attachment(doc, name, file, options = {}) ⇒ Object

PUT an attachment directly to CouchDB



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# File 'lib/sova/database.rb', line 95

def put_attachment(doc, name, file, options = {})
  docid = escape_docid(doc['_id'])
  uri = url_for_attachment(doc, name)
  response = HTTP.request(:put, uri, file, options)
  JSON.parse(response.body)
end

#recreate! ⇒ Object

Delete and re create the database



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# File 'lib/sova/database.rb', line 275

def recreate!
  delete!
  create!
rescue Sova::NotFound
ensure
  create!
end

#replicate_from(other_db, continuous = false, create_target = false) ⇒ Object

Replicates via “pulling” from another database to this database. Makes no attempt to deal with conflicts.



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# File 'lib/sova/database.rb', line 284

def replicate_from(other_db, continuous = false, create_target = false)
  replicate(other_db, continuous, :target => name, :create_target => create_target)
end

#replicate_to(other_db, continuous = false, create_target = false) ⇒ Object

Replicates via “pushing” to another database. Makes no attempt to deal with conflicts.



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# File 'lib/sova/database.rb', line 289

def replicate_to(other_db, continuous = false, create_target = false)
  replicate(other_db, continuous, :source => name, :create_target => create_target)
end

#save_doc(doc, bulk = false, batch = false) ⇒ Object

Save a document to CouchDB. This will use the _id field from the document as the id for PUT, or request a new UUID from CouchDB, if no _id is present on the document. IDs are attached to documents on the client side because POST has the curious property of being automatically retried by proxies in the event of network segmentation and lost responses.

If bulk is true (false by default) the document is cached for bulk-saving later. Bulk saving happens automatically when #bulk_save_cache limit is exceded, or on the next non bulk save.

If batch is true (false by default) the document is saved in batch mode, “used to achieve higher throughput at the cost of lower guarantees. When […] sent using this option, it is not immediately written to disk. Instead it is stored in memory on a per-user basis for a second or so (or the number of docs in memory reaches a certain point). After the threshold has passed, the docs are committed to disk. Instead of waiting for the doc to be written to disk before responding, CouchDB sends an HTTP 202 Accepted response immediately. batch=ok is not suitable for crucial data, but it ideal for applications like logging which can accept the risk that a small proportion of updates could be lost due to a crash.”



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# File 'lib/sova/database.rb', line 141

def save_doc(doc, bulk = false, batch = false)
  if doc['_attachments']
    doc['_attachments'] = encode_attachments(doc['_attachments'])
  end
  if bulk
    @bulk_save_cache << doc
    bulk_save if @bulk_save_cache.length >= @bulk_save_cache_limit
    return {"ok" => true} # Compatibility with Document#save
  elsif !bulk && @bulk_save_cache.length > 0
    bulk_save
  end
  result = if doc['_id']
    slug = escape_docid(doc['_id'])
    begin     
      uri = "#{@root}/#{slug}"
      uri << "?batch=ok" if batch
      HTTP.put uri, doc
    rescue Sova::NotFound
      p "resource not found when saving even tho an id was passed"
      slug = doc['_id'] = @server.next_uuid
      HTTP.put "#{@root}/#{slug}", doc
    end
  else
    begin
      slug = doc['_id'] = @server.next_uuid
      HTTP.put "#{@root}/#{slug}", doc
    rescue #old version of couchdb
      HTTP.post @root, doc
    end
  end
  if result['ok']
    doc['_id'] = result['id']
    doc['_rev'] = result['rev']
    doc.database = self if doc.respond_to?(:database=)
  end
  result
end

#slow_view(funcs, params = {}) ⇒ Object Also known as: temp_view

POST a temporary view function to CouchDB for querying. This is not recommended, as you don’t get any performance benefit from CouchDB’s materialized views. Can be quite slow on large databases.



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# File 'lib/sova/database.rb', line 56

def slow_view(funcs, params = {})
  keys = params.delete(:keys)
  funcs = funcs.merge({:keys => keys}) if keys
  url = Sova.paramify_url "#{@root}/_temp_view", params
  HTTP.post(url, funcs)
end

#to_s ⇒ Object

returns the database’s uri



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# File 'lib/sova/database.rb', line 27

def to_s
  @root
end

#update_doc(doc_id, params = {}, update_limit = 10) ⇒ Object

Updates the given doc by yielding the current state of the doc and trying to update update_limit times. Returns the new doc if the doc was successfully updated without hitting the limit



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# File 'lib/sova/database.rb', line 243

def update_doc(doc_id, params = {}, update_limit=10)
  resp = {'ok' => false}
  new_doc = nil
  last_fail = nil

  until resp['ok'] or update_limit <= 0
    doc = self.get(doc_id, params)  # grab the doc
    new_doc = yield doc # give it to the caller to be updated
    begin
      resp = self.save_doc new_doc # try to PUT the updated doc into the db
    rescue Sova::Conflict => e
      update_limit -= 1
      last_fail = e
    end
  end

  raise last_fail unless resp['ok']
  new_doc
end

#view(name, params = {}, &block) ⇒ Object

Query a CouchDB view as defined by a _design document. Accepts paramaters as described in wiki.apache.org/couchdb/HttpViewApi



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# File 'lib/sova/database.rb', line 68

def view(name, params = {}, &block)
  keys = params.delete(:keys)
  name = name.split('/') # I think this will always be length == 2, but maybe not...
  dname = name.shift
  vname = name.join('/')
  url = Sova.paramify_url "#{@root}/_design/#{dname}/_view/#{vname}", params
  if keys
    HTTP.post(url, {:keys => keys})
  else
    HTTP.get url
  end
end