feat(custom): add dynamic field replacement in custom requests #251

Introduce functionality to dynamically replace `$content` placeholders in custom request fields with the content of the first message. This enhances flexibility in custom request formatting. Added a test case to verify the new behavior

Author: phodal

core/src/main/kotlin/cc/unitmesh/devti/llms/custom/CustomSSEProcessor.kt

@@ -187,9 +187,34 @@ fun JsonObject.updateCustomBody(customRequest: String): JsonObject {
     return runCatching {
         buildJsonObject {
             // copy origin object
-            this@updateCustomBody.forEach { u, v -> put(u, v) }
-
             val customRequestJson = Json.parseToJsonElement(customRequest).jsonObject
+            customRequestJson["fields"]?.jsonObject?.let { fieldsObj ->
+                val messages: JsonArray = this@updateCustomBody["messages"]?.jsonArray ?: buildJsonArray {}
+                val contentOfFirstMessage = if (messages.isNotEmpty()) {
+                    messages.last().jsonObject["content"]?.jsonPrimitive?.content ?: ""
+                } else ""
+                fieldsObj.forEach { (fieldKey, fieldValue) ->
+                    if (fieldValue is JsonObject) {
+                        put(fieldKey, buildJsonObject {
+                            fieldValue.forEach { (subKey, subValue) ->
+                                if (subValue is JsonPrimitive && subValue.content == "\$content") {
+                                    put(subKey, JsonPrimitive(contentOfFirstMessage))
+                                } else {
+                                    put(subKey, subValue)
+                                }
+                            }
+                        })
+                    } else if (fieldValue is JsonPrimitive && fieldValue.content == "\$content") {
+                        put(fieldKey, JsonPrimitive(contentOfFirstMessage))
+                    } else {
+                        put(fieldKey, fieldValue)
+                    }
+                }
+
+                return@buildJsonObject
+            }
+
+            this@updateCustomBody.forEach { u, v -> put(u, v) }
             customRequestJson["customFields"]?.let { customFields ->
                 customFields.jsonObject.forEach { (key, value) ->
                     put(key, value)
@@ -224,6 +249,17 @@ fun JsonObject.updateCustomBody(customRequest: String): JsonObject {
 
 fun CustomRequest.updateCustomFormat(format: String): String {
     val requestContentOri = Json.encodeToString<CustomRequest>(this)
-    return Json.parseToJsonElement(requestContentOri)
-        .jsonObject.updateCustomBody(format).toString()
+    val updateCustomBody = Json.parseToJsonElement(requestContentOri)
+        .jsonObject.updateCustomBody(format)
+
+    return updateCustomBody.toString()
 }
+
+fun JsonObject.removeFields(vararg fields: String): JsonObject {
+    return JsonObject(
+        toMutableMap()
+            .apply {
+                fields.forEach { remove(it) }
+            }
+    )
+}

core/src/test/kotlin/cc/unitmesh/devti/llms/custom/CustomLLMProviderTest.kt

@@ -82,4 +82,26 @@ class CustomLLMProviderTest {
         """.trimIndent(), request)
     }
 
+    @Test
+    fun shouldReplaceUserInputToFieldWhenUserUseField() {
+        val customRequestFormat = """
+            {
+              "fields": {
+                "inputs": {
+                  "feature": "${'$'}content"
+                },
+                "response_mode": "streaming"
+              }
+            }
+        """.trimIndent()
+
+        val customRequest = CustomRequest(listOf(
+                Message("robot", "robot-hello")
+        ))
+
+        val request = customRequest.updateCustomFormat(customRequestFormat)
+        assertEquals("""
+            {"inputs":{"feature":"robot-hello"},"response_mode":"streaming"}
+        """.trimIndent(), request)
+    }
 }