# The ChangesetController is the RESTful interface to Changeset objects
module Api
class ChangesetsController < ApiController
require "xml/libxml"
before_action :check_api_writable, :only => [:create, :update, :upload, :subscribe, :unsubscribe]
before_action :check_api_readable, :except => [:create, :update, :upload, :download, :query, :subscribe, :unsubscribe]
before_action :authorize, :only => [:create, :update, :upload, :close, :subscribe, :unsubscribe]
authorize_resource
before_action :require_public_data, :only => [:create, :update, :upload, :close, :subscribe, :unsubscribe]
before_action :set_request_formats, :except => [:create, :close, :upload]
around_action :api_call_handle_error
around_action :api_call_timeout, :except => [:upload]
# Helper methods for checking consistency
include ConsistencyValidations
##
# Return XML giving the basic info about the changeset. Does not
# return anything about the nodes, ways and relations in the changeset.
def show
@changeset = Changeset.find(params[:id])
@include_discussion = params[:include_discussion].presence
render "changeset"
respond_to do |format|
format.xml
format.json
end
end
# Create a changeset from XML.
def create
assert_method :put
cs = Changeset.from_xml(request.raw_post, :create => true)
# Assume that Changeset.from_xml has thrown an exception if there is an error parsing the xml
cs.user = current_user
cs.save_with_tags!
# Subscribe user to changeset comments
cs.subscribers << current_user
render :plain => cs.id.to_s
end
##
# marks a changeset as closed. this may be called multiple times
# on the same changeset, so is idempotent.
def close
assert_method :put
changeset = Changeset.find(params[:id])
check_changeset_consistency(changeset, current_user)
# to close the changeset, we'll just set its closed_at time to
# now. this might not be enough if there are concurrency issues,
# but we'll have to wait and see.
changeset.set_closed_time_now
changeset.save!
head :ok
end
##
# Upload a diff in a single transaction.
#
# This means that each change within the diff must succeed, i.e: that
# each version number mentioned is still current. Otherwise the entire
# transaction *must* be rolled back.
#
# Furthermore, each element in the diff can only reference the current
# changeset.
#
# Returns: a diffResult document, as described in
# http://wiki.openstreetmap.org/wiki/OSM_Protocol_Version_0.6
def upload
# only allow POST requests, as the upload method is most definitely
# not idempotent, as several uploads with placeholder IDs will have
# different side-effects.
# see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2
assert_method :post
changeset = Changeset.find(params[:id])
check_changeset_consistency(changeset, current_user)
diff_reader = DiffReader.new(request.raw_post, changeset)
Changeset.transaction do
result = diff_reader.commit
render :xml => result.to_s
end
end
##
# download the changeset as an osmChange document.
#
# to make it easier to revert diffs it would be better if the osmChange
# format were reversible, i.e: contained both old and new versions of
# modified elements. but it doesn't at the moment...
#
# this method cannot order the database changes fully (i.e: timestamp and
# version number may be too coarse) so the resulting diff may not apply
# to a different database. however since changesets are not atomic this
# behaviour cannot be guaranteed anyway and is the result of a design
# choice.
def download
changeset = Changeset.find(params[:id])
# get all the elements in the changeset which haven't been redacted
# and stick them in a big array.
elements = [changeset.old_nodes.unredacted,
changeset.old_ways.unredacted,
changeset.old_relations.unredacted].flatten
# sort the elements by timestamp and version number, as this is the
# almost sensible ordering available. this would be much nicer if
# global (SVN-style) versioning were used - then that would be
# unambiguous.
elements.sort! do |a, b|
if a.timestamp == b.timestamp
a.version <=> b.version
else
a.timestamp <=> b.timestamp
end
end
# generate an output element for each operation. note: we avoid looking
# at the history because it is simpler - but it would be more correct to
# check these assertions.
@created = []
@modified = []
@deleted = []
elements.each do |elt|
if elt.version == 1
# first version, so it must be newly-created.
@created << elt
elsif elt.visible
# must be a modify
@modified << elt
else
# if the element isn't visible then it must have been deleted
@deleted << elt
end
end
respond_to do |format|
format.xml
end
end
##
# query changesets by bounding box, time, user or open/closed status.
def query
raise OSM::APIBadUserInput, "cannot use order=oldest with time" if params[:time] && params[:order] == "oldest"
# find any bounding box
bbox = BoundingBox.from_bbox_params(params) if params["bbox"]
# create the conditions that the user asked for. some or all of
# these may be nil.
changesets = Changeset.all
changesets = conditions_bbox(changesets, bbox)
changesets = conditions_user(changesets, params["user"], params["display_name"])
changesets = conditions_time(changesets, params["time"])
changesets = conditions_from_to(changesets, params["from"], params["to"])
changesets = conditions_open(changesets, params["open"])
changesets = conditions_closed(changesets, params["closed"])
changesets = conditions_ids(changesets, params["changesets"])
# sort the changesets
changesets = if params[:order] == "oldest"
changesets.order(:created_at => :asc)
else
changesets.order(:created_at => :desc)
end
# limit the result
changesets = changesets.limit(result_limit)
# preload users, tags and comments, and render result
@changesets = changesets.preload(:user, :changeset_tags, :comments)
render "changesets"
respond_to do |format|
format.xml
format.json
end
end
##
# updates a changeset's tags. none of the changeset's attributes are
# user-modifiable, so they will be ignored.
#
# changesets are not (yet?) versioned, so we don't have to deal with
# history tables here. changesets are locked to a single user, however.
#
# after succesful update, returns the XML of the changeset.
def update
# request *must* be a PUT.
assert_method :put
@changeset = Changeset.find(params[:id])
new_changeset = Changeset.from_xml(request.raw_post)
check_changeset_consistency(@changeset, current_user)
@changeset.update_from(new_changeset, current_user)
render "changeset"
respond_to do |format|
format.xml
format.json
end
end
##
# Adds a subscriber to the changeset
def subscribe
# Check the arguments are sane
raise OSM::APIBadUserInput, "No id was given" unless params[:id]
# Extract the arguments
id = params[:id].to_i
# Find the changeset and check it is valid
changeset = Changeset.find(id)
raise OSM::APIChangesetAlreadySubscribedError, changeset if changeset.subscribers.exists?(current_user.id)
# Add the subscriber
changeset.subscribers << current_user
# Return a copy of the updated changeset
@changeset = changeset
render "changeset"
respond_to do |format|
format.xml
format.json
end
end
##
# Removes a subscriber from the changeset
def unsubscribe
# Check the arguments are sane
raise OSM::APIBadUserInput, "No id was given" unless params[:id]
# Extract the arguments
id = params[:id].to_i
# Find the changeset and check it is valid
changeset = Changeset.find(id)
raise OSM::APIChangesetNotSubscribedError, changeset unless changeset.subscribers.exists?(current_user.id)
# Remove the subscriber
changeset.subscribers.delete(current_user)
# Return a copy of the updated changeset
@changeset = changeset
render "changeset"
respond_to do |format|
format.xml
format.json
end
end
private
#------------------------------------------------------------
# utility functions below.
#------------------------------------------------------------
##
# if a bounding box was specified do some sanity checks.
# restrict changesets to those enclosed by a bounding box
# we need to return both the changesets and the bounding box
def conditions_bbox(changesets, bbox)
if bbox
bbox.check_boundaries
bbox = bbox.to_scaled
changesets.where("min_lon < ? and max_lon > ? and min_lat < ? and max_lat > ?",
bbox.max_lon.to_i, bbox.min_lon.to_i,
bbox.max_lat.to_i, bbox.min_lat.to_i)
else
changesets
end
end
##
# restrict changesets to those by a particular user
def conditions_user(changesets, user, name)
if user.nil? && name.nil?
changesets
else
# shouldn't provide both name and UID
raise OSM::APIBadUserInput, "provide either the user ID or display name, but not both" if user && name
# use either the name or the UID to find the user which we're selecting on.
u = if name.nil?
# user input checking, we don't have any UIDs < 1
raise OSM::APIBadUserInput, "invalid user ID" if user.to_i < 1
u = User.find_by(:id => user.to_i)
else
u = User.find_by(:display_name => name)
end
# make sure we found a user
raise OSM::APINotFoundError if u.nil?
# should be able to get changesets of public users only, or
# our own changesets regardless of public-ness.
unless u.data_public?
# get optional user auth stuff so that users can see their own
# changesets if they're non-public
setup_user_auth
raise OSM::APINotFoundError if current_user.nil? || current_user != u
end
changesets.where(:user_id => u.id)
end
end
##
# restrict changesets to those during a particular time period
def conditions_time(changesets, time)
if time.nil?
changesets
elsif time.count(",") == 1
# if there is a range, i.e: comma separated, then the first is
# low, second is high - same as with bounding boxes.
# check that we actually have 2 elements in the array
times = time.split(",")
raise OSM::APIBadUserInput, "bad time range" if times.size != 2
from, to = times.collect { |t| Time.parse(t).utc }
changesets.where("closed_at >= ? and created_at <= ?", from, to)
else
# if there is no comma, assume its a lower limit on time
changesets.where("closed_at >= ?", Time.parse(time).utc)
end
# stupid Time seems to throw both of these for bad parsing, so
# we have to catch both and ensure the correct code path is taken.
rescue ArgumentError, RuntimeError => e
raise OSM::APIBadUserInput, e.message.to_s
end
##
# restrict changesets to those opened during a particular time period
# works similar to from..to of notes controller, including the requirement of 'from' when specifying 'to'
def conditions_from_to(changesets, from, to)
if from
begin
from = Time.parse(from).utc
rescue ArgumentError
raise OSM::APIBadUserInput, "Date #{from} is in a wrong format"
end
begin
to = if to
Time.parse(to).utc
else
Time.now.utc
end
rescue ArgumentError
raise OSM::APIBadUserInput, "Date #{to} is in a wrong format"
end
changesets.where(:created_at => from..to)
else
changesets
end
end
##
# return changesets which are open (haven't been closed yet)
# we do this by seeing if the 'closed at' time is in the future. Also if we've
# hit the maximum number of changes then it counts as no longer open.
# if parameter 'open' is nill then open and closed changesets are returned
def conditions_open(changesets, open)
if open.nil?
changesets
else
changesets.where("closed_at >= ? and num_changes <= ?",
Time.now.utc, Changeset::MAX_ELEMENTS)
end
end
##
# query changesets which are closed
# ('closed at' time has passed or changes limit is hit)
def conditions_closed(changesets, closed)
if closed.nil?
changesets
else
changesets.where("closed_at < ? or num_changes > ?",
Time.now.utc, Changeset::MAX_ELEMENTS)
end
end
##
# query changesets by a list of ids
# (either specified as array or comma-separated string)
def conditions_ids(changesets, ids)
if ids.nil?
changesets
elsif ids.empty?
raise OSM::APIBadUserInput, "No changesets were given to search for"
else
ids = ids.split(",").collect(&:to_i)
changesets.where(:id => ids)
end
end
##
# Get the maximum number of results to return
def result_limit
if params[:limit]
if params[:limit].to_i.positive? && params[:limit].to_i <= Settings.max_changeset_query_limit
params[:limit].to_i
else
raise OSM::APIBadUserInput, "Changeset limit must be between 1 and #{Settings.max_changeset_query_limit}"
end
else
Settings.default_changeset_query_limit
end
end
end
end