iqdb: proxy iqdb searches through danbooru.

Previously the search form on the /iqdb_queries page submitted directly
to the iqdb service (karasuma.donmai.us), which redirected back to
Danbooru with the search results.

This was different than API requests, which submitted to
/iqdb_queries.json which proxied the call to iqdb through Danbooru.
Because of this, searches on the /iqdb_queries page had different
behavior than API requests. Things like filesize limits and referrer
spoofing were handled differently.

Now searches on the /iqdb_queries page submit directly to Danbooru. This
is simpler and it means that API requests and HTML requests have the
same behavior.

app/controllers/iqdb_queries_controller.rb

@@ -2,16 +2,12 @@ class IqdbQueriesController < ApplicationController
   respond_to :html, :json, :xml, :js
 
   def show
-    if params[:url]
-      url = Sources::Strategies.find(params[:url]).image_url
-      @matches = IqdbProxy.query(url, params[:limit], params[:similarity])
-    elsif params[:post_id]
-      url = Post.find(params[:post_id]).preview_file_url
-      @matches = IqdbProxy.query(url, params[:limit], params[:similarity])
-    elsif params[:matches]
-      @matches = IqdbProxy.decorate_posts(JSON.parse(params[:matches]))
-    end
+    # XXX allow bare search params for backwards compatibility.
+    search_params.merge!(params.slice(:url, :post_id, :limit, :similarity).permit!)
 
-    respond_with(@matches)
+    @matches = IqdbProxy.search(search_params)
+    respond_with(@matches, template: "iqdb_queries/show")
   end
+
+  alias create show
 end

app/helpers/application_helper.rb

@@ -164,11 +164,11 @@ module ApplicationHelper
     end
   end
 
-  def search_form_for(url, classes: "inline-form", &block)
+  def search_form_for(url, classes: "inline-form", method: :get, &block)
     defaults = { required: false }
     html_options = { autocomplete: "off", class: "search-form #{classes}" }
 
-    simple_form_for(:search, method: :get, url: url, defaults: defaults, html: html_options, &block)
+    simple_form_for(:search, method: method, url: url, defaults: defaults, html: html_options, &block)
   end
 
   def body_attributes(user = CurrentUser.user)

app/logical/iqdb_proxy.rb

@@ -1,15 +1,37 @@
 class IqdbProxy
-  def self.query(url, limit, similarity)
+  def self.search(params)
     raise NotImplementedError unless Danbooru.config.iqdbs_server.present?
 
-    limit ||= 20
-    similarity ||= 0.0
+    limit = params[:limit].presence || 20
+    limit = limit.to_i.clamp(1, 100)
+    similarity = params[:similarity].to_f.clamp(0.0, 100.0)
+
+    if params[:file].present?
+      results = query_file(params[:file], limit)
+    elsif params[:url].present?
+      url = Sources::Strategies.find(params[:url]).image_url
+      results = query_url(url, limit)
+    elsif params[:post_id].present?
+      url = Post.find(params[:post_id]).preview_file_url
+      results = query_url(url, limit)
+    else
+      results = []
+    end
+
+    results = results.select { |result| result["score"] >= similarity }.take(limit)
+    decorate_posts(results)
+  end
+
+  def self.query_url(url, limit)
     query = { url: url, limit: limit }
     response = HTTParty.get("#{Danbooru.config.iqdbs_server}/similar", query: query, **Danbooru.config.httparty_options)
+    response.parsed_response
+  end
 
-    json = decorate_posts(response.parsed_response)
-    json = json.select { |result| result["score"] >= similarity.to_f }.take(limit.to_i)
-    json
+  def self.query_file(file, limit)
+    body = { file: file, limit: limit }
+    response = HTTParty.post("#{Danbooru.config.iqdbs_server}/similar", body: body, **Danbooru.config.httparty_options)
+    response.parsed_response
   end
 
   def self.decorate_posts(json)

app/views/iqdb_queries/show.html.erb

@@ -2,22 +2,13 @@
   <div id="a-check">
     <h1>Similar Images Search</h1>
     <section>
-      <p>You can upload a file or paste a URL to perform an image similarity search with every upload on <%= Danbooru.config.app_name %>. Note that this page will redirect you to <%= link_to "IQDBS", Danbooru.config.iqdbs_server %>. You will be redirected back here once the search is executed.</p>
+      <p>Paste a URL or upload a file to perform a reverse image search on <%= Danbooru.config.app_name %>.</p>
 
-      <%= form_tag("#{Danbooru.config.iqdbs_server}/similar", method: :post, class: "simple_form", multipart: true ) do %>
-        <%= hidden_field_tag "callback", iqdb_queries_url %>
-
-        <div class="input string optional">
-          <%= label_tag "url", "URL", class: "string optional" %>
-          <%= text_field_tag "url", params[:url] %>
-        </div>
-
-        <div class="input string optional fallback">
-          <%= label_tag "file", "File", class: "string optional" %>
-          <%= file_field_tag :file, :size => 50 %>
-        </div>
-
-        <%= submit_tag "Search" %>
+      <%= search_form_for(iqdb_queries_path, method: :post) do |f| %>
+        <%= f.input :post_id, label: "Post ID", input_html: { value: params[:search][:post_id] } %>
+        <%= f.input :url, input_html: { value: params[:search][:url] } %>
+        <%= f.input :file, as: :file %>
+        <%= f.submit "Search" %>
       <% end %>
     </section>
 

config/routes.rb

@@ -153,7 +153,7 @@ Rails.application.routes.draw do
     resource :visit, :controller => "forum_topic_visits"
   end
   resources :ip_bans
-  resource :iqdb_queries, :only => [:show]  do
+  resource :iqdb_queries, :only => [:show, :create]  do
     collection do
       get :preview
       get :check, to: redirect {|path_params, req| "/iqdb_queries?#{req.query_string}"}