update content format to image_url input for gpt vision

Author: leafo

examples/example6.lua

@@ -0,0 +1,20 @@
+-- this shows how to provide an image
+
+local openai = require("openai")
+local client = openai.new(os.getenv("OPENAI_API_KEY"))
+
+local status, response = client:chat({
+  {
+    role = "user",
+    content = {
+      { type = "image_url", image_url = "https://leafo.net/hi.png" },
+      { type = "text", text = "Describe this image" }
+    }
+  }
+}, {
+  model = "gpt-4-vision-preview"
+})
+
+if status == 200 then
+  print(response.choices[1].message.content)
+end

openai/init.lua

@@ -6,14 +6,24 @@ local types
 types = require("tableshape").types
 local parse_url = require("socket.url").parse
 local empty = (types["nil"] + types.literal(cjson.null)):describe("nullable")
+local content_format = types.string + types.array_of(types.one_of({
+  types.shape({
+    type = "text",
+    text = types.string
+  }),
+  types.shape({
+    type = "image_url",
+    image_url = types.string
+  })
+}))
 local test_message = types.one_of({
   types.shape({
     role = types.one_of({
       "system",
       "user",
       "assistant"
     }),
-    content = empty + types.string,
+    content = empty + content_format,
     name = empty + types.string,
     function_call = empty + types.table
   }),

openai/init.moon

@@ -11,10 +11,15 @@ parse_url = require("socket.url").parse
 
 empty = (types.nil + types.literal(cjson.null))\describe "nullable"
 
+content_format = types.string + types.array_of types.one_of {
+  types.shape { type: "text", text: types.string }
+  types.shape { type: "image_url", image_url: types.string }
+}
+
 test_message = types.one_of {
   types.shape {
     role: types.one_of {"system", "user", "assistant"}
-    content: empty + types.string -- this can be empty when function_call is set
+    content: empty + content_format -- this can be empty when function_call is set
     name: empty + types.string
     function_call: empty + types.table
   }