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database.rb
397 lines (350 loc) · 13.1 KB
/
database.rb
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require 'cgi'
require "base64"
module CouchRest
class Database
attr_reader :server, :host, :name, :root, :uri
attr_accessor :bulk_save_cache_limit
# Create a CouchRest::Database adapter for the supplied CouchRest::Server
# and database name.
#
# ==== Parameters
# server<CouchRest::Server>:: database host
# name<String>:: database name
#
def initialize(server, name)
@name = name
@server = server
@host = server.uri
@uri = "/#{name.gsub('/','%2F')}"
@root = host + uri
@streamer = Streamer.new
@bulk_save_cache = []
@bulk_save_cache_limit = 500 # must be smaller than the uuid count
end
# == Database information and manipulation methods
# returns the database's uri
def to_s
@root
end
# GET the database info from CouchDB
def info
CouchRest.get @root
end
# Compact the database, removing old document revisions and optimizing space use.
def compact!
CouchRest.post "#{@root}/_compact"
end
# Create the database
def create!
bool = server.create_db(@name) rescue false
bool && true
end
# Delete and re create the database
def recreate!
delete!
create!
rescue RestClient::ResourceNotFound
ensure
create!
end
# Replicates via "pulling" from another database to this database. Makes no attempt to deal with conflicts.
def replicate_from(other_db, continuous = false, create_target = false, doc_ids = nil)
replicate(other_db, continuous, :target => name, :create_target => create_target, :doc_ids => doc_ids)
end
# Replicates via "pushing" to another database. Makes no attempt to deal with conflicts.
def replicate_to(other_db, continuous = false, create_target = false, doc_ids = nil)
replicate(other_db, continuous, :source => name, :create_target => create_target, :doc_ids => doc_ids)
end
# DELETE the database itself. This is not undoable and could be rather
# catastrophic. Use with care!
def delete!
CouchRest.delete @root
end
# == Retrieving and saving single documents
# GET a document from CouchDB, by id. Returns a Document or Design.
def get(id, params = {})
slug = escape_docid(id)
url = CouchRest.paramify_url("#{@root}/#{slug}", params)
result = CouchRest.get(url)
return result unless result.is_a?(Hash)
doc = if /^_design/ =~ result["_id"]
Design.new(result)
else
Document.new(result)
end
doc.database = self
doc
end
# Save a document to CouchDB. This will use the <tt>_id</tt> field from
# the document as the id for PUT, or request a new UUID from CouchDB, if
# no <tt>_id</tt> 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 <tt>bulk</tt> 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 <tt>batch</tt> 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."
def save_doc(doc, bulk = false, batch = false)
doc = Document.new doc
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
CouchRest.put uri, doc
rescue RestClient::ResourceNotFound
p "resource not found when saving even tho an id was passed"
slug = doc['_id'] = @server.next_uuid
CouchRest.put "#{@root}/#{slug}", doc
end
else
begin
slug = doc['_id'] = @server.next_uuid
CouchRest.put "#{@root}/#{slug}", doc
rescue #old version of couchdb
CouchRest.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
# Save a document to CouchDB in bulk mode. See #save_doc's +bulk+ argument.
def bulk_save_doc(doc)
save_doc(doc, true)
end
# Save a document to CouchDB in batch mode. See #save_doc's +batch+ argument.
def batch_save_doc(doc)
save_doc(doc, false, true)
end
# 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.
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
CouchRest.post "#{@root}/_bulk_docs", {:docs => docs}
end
alias :bulk_delete :bulk_save
# DELETE the document from CouchDB that has the given <tt>_id</tt> and
# <tt>_rev</tt>.
#
# If <tt>bulk</tt> 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.
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'])
CouchRest.delete "#{@root}/#{slug}?rev=#{doc['_rev']}"
end
# COPY an existing document to a new id. If the destination id currently exists, a rev must be provided.
# <tt>dest</tt> can take one of two forms if overwriting: "id_to_overwrite?rev=revision" or the actual doc
# hash with a '_rev' key
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
CouchRest.copy "#{@root}/#{slug}", destination
end
# Updates the given doc by yielding the current state of the doc
# and trying to update update_limit times. Returns the doc
# if successfully updated without hitting the limit.
# If the limit is reached, the last execption will be raised.
def update_doc(doc_id, params = {}, update_limit = 10)
resp = {'ok' => false}
last_fail = nil
until resp['ok'] or update_limit <= 0
doc = self.get(doc_id, params)
yield doc
begin
resp = self.save_doc doc
rescue RestClient::RequestFailed => e
if e.http_code == 409 # Update collision
update_limit -= 1
last_fail = e
else
raise e
end
end
end
raise last_fail unless resp['ok']
doc
end
# == View and multi-document based queries
# Query a CouchDB view as defined by a <tt>_design</tt> document. Accepts
# paramaters as described in http://wiki.apache.org/couchdb/HttpViewApi
def view(name, params = {}, payload = {}, &block)
payload['keys'] = params.delete(:keys) if params[:keys]
# Try recognising the name, otherwise assume already prepared
view_path = name_to_view_path(name)
url = CouchRest.paramify_url "#{@root}/#{view_path}", params
if block_given?
if !payload.empty?
@streamer.post url, payload, &block
else
@streamer.get url, &block
end
else
if !payload.empty?
CouchRest.post url, payload
else
CouchRest.get url
end
end
end
# 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.
def temp_view(payload, params = {}, &block)
view('_temp_view', params, payload, &block)
end
alias :slow_view :temp_view
# Query the <tt>_all_docs</tt> view. Accepts all the same arguments as view.
def all_docs(params = {}, payload = {}, &block)
view("_all_docs", params, payload, &block)
end
alias :documents :all_docs
# Query CouchDB's special <tt>_changes</tt> feed for the latest.
# All standard CouchDB options can be provided.
#
# Warning: sending :feed => 'continuous' will cause your code to block
# indefinetly while waiting for changes. You might want to look-up an
# alternative to this.
def changes(params = {}, payload = {}, &block)
view("_changes", params, payload, &block)
end
# Query a CouchDB-Lucene search view
def fti(name, params={})
# -> http://localhost:5984/yourdb/_fti/YourDesign/by_name?include_docs=true&q=plop*'
view("_fti/#{name}", params)
end
alias :search :fti
# load a set of documents by passing an array of ids
def get_bulk(ids)
all_docs(:keys => ids, :include_docs => true)
end
alias :bulk_load :get_bulk
# == Handling attachments
# GET an attachment directly from CouchDB
def fetch_attachment(doc, name)
uri = url_for_attachment(doc, name)
CouchRest.get uri, :raw => true
end
# PUT an attachment directly to CouchDB
def put_attachment(doc, name, file, options = {})
docid = escape_docid(doc['_id'])
uri = url_for_attachment(doc, name)
CouchRest.put(uri, file, options.merge(:raw => true))
end
# DELETE an attachment directly from CouchDB
def delete_attachment(doc, name, force=false)
uri = url_for_attachment(doc, name)
# this needs a rev
begin
CouchRest.delete(uri)
rescue Exception => error
if force
# get over a 409
doc = get(doc['_id'])
uri = url_for_attachment(doc, name)
CouchRest.delete(uri)
else
error
end
end
end
private
def replicate(other_db, continuous, options)
raise ArgumentError, "must provide a CouchReset::Database" unless other_db.kind_of?(CouchRest::Database)
raise ArgumentError, "must provide a target or source option" unless (options.key?(:target) || options.key?(:source))
payload = options
if options.has_key?(:target)
payload['source'] = other_db.root
else
payload['target'] = other_db.root
end
payload['continuous'] = continuous
payload['doc_ids'] = options[:doc_ids] if options[:doc_ids]
CouchRest.post "#{@host}/_replicate", payload
end
def uri_for_attachment(doc, name)
if doc.is_a?(String)
puts "CouchRest::Database#fetch_attachment will eventually require a doc as the first argument, not a doc.id"
docid = doc
rev = nil
else
docid = doc['_id']
rev = doc['_rev']
end
docid = escape_docid(docid)
name = CGI.escape(name)
rev = "?rev=#{doc['_rev']}" if rev
"/#{docid}/#{name}#{rev}"
end
def url_for_attachment(doc, name)
@root + uri_for_attachment(doc, name)
end
def escape_docid id
/^_design\/(.*)/ =~ id ? "_design/#{CGI.escape($1)}" : CGI.escape(id)
end
def encode_attachments(attachments)
attachments.each do |k,v|
next if v['stub']
v['data'] = base64(v['data'])
end
attachments
end
def base64(data)
Base64.encode64(data).gsub(/\s/,'')
end
# Convert a simplified view name into a complete view path. If
# the name already starts with a "_" no alterations will be made.
def name_to_view_path(name)
name =~ /^([^_].+?)\/(.*)$/ ? "_design/#{$1}/_view/#{$2}" : name
end
end
end