FEATURE: add support for final stable diffusion xl model (#122)

config/settings.yml

@@ -103,10 +103,11 @@ plugins:
   ai_stability_api_url:
     default: "https://api.stability.ai"
   ai_stability_engine:
-    default: "stable-diffusion-xl-beta-v2-2-2"
+    default: "stable-diffusion-xl-1024-v1-0"
     type: enum
     choices:
-      - "stable-diffusion-xl-beta-v2-2-2"
+      - "stable-diffusion-xl-1024-v1-0"
+      - "stable-diffusion-768-v2-1"
       - "stable-diffusion-v1-5"
   ai_hugging_face_api_url:
     default: ""

lib/shared/inference/stability_generator.rb

@@ -3,7 +3,7 @@
 module ::DiscourseAi
   module Inference
     class StabilityGenerator
-      def self.perform!(prompt)
+      def self.perform!(prompt, width: nil, height: nil)
         headers = {
           "Referer" => Discourse.base_url,
           "Content-Type" => "application/json",
@@ -11,12 +11,32 @@ module ::DiscourseAi
           "Authorization" => "Bearer #{SiteSetting.ai_stability_api_key}",
         }
 
+        sdxl_allowed_dimentions = [
+          [1024, 1024],
+          [1152, 896],
+          [1216, 832],
+          [1344, 768],
+          [1536, 640],
+          [640, 1536],
+          [768, 1344],
+          [832, 1216],
+          [896, 1152],
+        ]
+
+        if (!width && !height)
+          if SiteSetting.ai_stability_engine.include? "xl"
+            width, height = sdxl_allowed_dimentions[0]
+          else
+            width, height = [512, 512]
+          end
+        end
+
         payload = {
           text_prompts: [{ text: prompt }],
           cfg_scale: 7,
           clip_guidance_preset: "FAST_BLUE",
-          height: 512,
-          width: 512,
+          height: width,
+          width: height,
           samples: 4,
           steps: 30,
         }
@@ -27,7 +47,12 @@ module ::DiscourseAi
 
         response = Faraday.post("#{base_url}/#{endpoint}", payload.to_json, headers)
 
-        raise Net::HTTPBadResponse if response.status != 200
+        if response.status != 200
+          Rails.logger.error(
+            "AI stability generator failed with status #{response.status}: #{response.body}}",
+          )
+          raise Net::HTTPBadResponse
+        end
 
         JSON.parse(response.body, symbolize_names: true)
       end

spec/shared/inference/stability_generator_spec.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+require "rails_helper"
+
+describe DiscourseAi::Inference::StabilityGenerator do
+  def gen(prompt)
+    DiscourseAi::Inference::StabilityGenerator.perform!(prompt)
+  end
+
+  it "sets dimentions to 512x512 for non XL model" do
+    SiteSetting.ai_stability_engine = "stable-diffusion-v1-5"
+    SiteSetting.ai_stability_api_url = "http://www.a.b.c"
+    SiteSetting.ai_stability_api_key = "123"
+
+    stub_request(:post, "http://www.a.b.c/v1/generation/stable-diffusion-v1-5/text-to-image")
+      .with do |request|
+        json = JSON.parse(request.body)
+        expect(json["text_prompts"][0]["text"]).to eq("a cow")
+        expect(json["width"]).to eq(512)
+        expect(json["height"]).to eq(512)
+        expect(request.headers["Authorization"]).to eq("Bearer 123")
+        expect(request.headers["Content-Type"]).to eq("application/json")
+        true
+      end
+      .to_return(status: 200, body: "{}", headers: {})
+
+    gen("a cow")
+  end
+
+  it "sets dimentions to 1024x1024 for XL model" do
+    SiteSetting.ai_stability_engine = "stable-diffusion-xl-1024-v1-0"
+    SiteSetting.ai_stability_api_url = "http://www.a.b.c"
+    SiteSetting.ai_stability_api_key = "123"
+    stub_request(
+      :post,
+      "http://www.a.b.c/v1/generation/stable-diffusion-xl-1024-v1-0/text-to-image",
+    )
+      .with do |request|
+        json = JSON.parse(request.body)
+        expect(json["text_prompts"][0]["text"]).to eq("a cow")
+        expect(json["width"]).to eq(1024)
+        expect(json["height"]).to eq(1024)
+        expect(request.headers["Authorization"]).to eq("Bearer 123")
+        expect(request.headers["Content-Type"]).to eq("application/json")
+        true
+      end
+      .to_return(status: 200, body: "{}", headers: {})
+
+    gen("a cow")
+  end
+end