Feature/added litellm component (#4327)

* feat: add ChatLitellm component and LitellmApi credential

* fix: lint errors

* Update LLMFilterCompressionRetriever.ts

---------

Co-authored-by: Henry Heng <henryheng@flowiseai.com>

packages/components/credentials/LitellmApi.credential.ts

@@ -0,0 +1,23 @@
+import { INodeParams, INodeCredential } from '../src/Interface'
+
+class LitellmApi implements INodeCredential {
+    label: string
+    name: string
+    version: number
+    inputs: INodeParams[]
+
+    constructor() {
+        this.label = 'Litellm API'
+        this.name = 'litellmApi'
+        this.version = 1.0
+        this.inputs = [
+            {
+                label: 'API Key',
+                name: 'litellmApiKey',
+                type: 'password'
+            }
+        ]
+    }
+}
+
+module.exports = { credClass: LitellmApi }

packages/components/nodes/chatmodels/ChatLitellm/ChatLitellm.ts

@@ -0,0 +1,135 @@
+import { OpenAIChatInput, ChatOpenAI } from '@langchain/openai'
+import { BaseCache } from '@langchain/core/caches'
+import { BaseLLMParams } from '@langchain/core/language_models/llms'
+import { ICommonObject, INode, INodeData, INodeParams } from '../../../src/Interface'
+import { getBaseClasses, getCredentialData, getCredentialParam } from '../../../src/utils'
+
+class ChatLitellm_ChatModels implements INode {
+    label: string
+    name: string
+    version: number
+    type: string
+    icon: string
+    category: string
+    description: string
+    baseClasses: string[]
+    credential: INodeParams
+    inputs: INodeParams[]
+
+    constructor() {
+        this.label = 'ChatLitellm'
+        this.name = 'chatLitellm'
+        this.version = 1.0
+        this.type = 'ChatLitellm'
+        this.icon = 'litellm.jpg'
+        this.category = 'Chat Models'
+        this.description = 'Connect to a Litellm server using OpenAI-compatible API'
+        this.baseClasses = [this.type, 'BaseChatModel', ...getBaseClasses(ChatOpenAI)]
+        this.credential = {
+            label: 'Connect Credential',
+            name: 'credential',
+            type: 'credential',
+            credentialNames: ['litellmApi'],
+            optional: true
+        }
+        this.inputs = [
+            {
+                label: 'Cache',
+                name: 'cache',
+                type: 'BaseCache',
+                optional: true
+            },
+            {
+                label: 'Base URL',
+                name: 'basePath',
+                type: 'string',
+                placeholder: 'http://localhost:8000'
+            },
+            {
+                label: 'Model Name',
+                name: 'modelName',
+                type: 'string',
+                placeholder: 'model_name'
+            },
+            {
+                label: 'Temperature',
+                name: 'temperature',
+                type: 'number',
+                step: 0.1,
+                default: 0.9,
+                optional: true
+            },
+            {
+                label: 'Streaming',
+                name: 'streaming',
+                type: 'boolean',
+                default: true,
+                optional: true,
+                additionalParams: true
+            },
+            {
+                label: 'Max Tokens',
+                name: 'maxTokens',
+                type: 'number',
+                step: 1,
+                optional: true,
+                additionalParams: true
+            },
+            {
+                label: 'Top P',
+                name: 'topP',
+                type: 'number',
+                step: 0.1,
+                optional: true,
+                additionalParams: true
+            },
+            {
+                label: 'Timeout',
+                name: 'timeout',
+                type: 'number',
+                step: 1,
+                optional: true,
+                additionalParams: true
+            }
+        ]
+    }
+
+    async init(nodeData: INodeData, _: string, options: ICommonObject): Promise<any> {
+        const cache = nodeData.inputs?.cache as BaseCache
+        const basePath = nodeData.inputs?.basePath as string
+        const modelName = nodeData.inputs?.modelName as string
+        const temperature = nodeData.inputs?.temperature as string
+        const streaming = nodeData.inputs?.streaming as boolean
+        const maxTokens = nodeData.inputs?.maxTokens as string
+        const topP = nodeData.inputs?.topP as string
+        const timeout = nodeData.inputs?.timeout as string
+
+        const credentialData = await getCredentialData(nodeData.credential ?? '', options)
+        const apiKey = getCredentialParam('litellmApiKey', credentialData, nodeData)
+
+        const obj: Partial<OpenAIChatInput> &
+            BaseLLMParams & { openAIApiKey?: string } & { configuration?: { baseURL?: string; defaultHeaders?: ICommonObject } } = {
+            temperature: parseFloat(temperature),
+            modelName,
+            streaming: streaming ?? true
+        }
+
+        if (basePath) {
+            obj.configuration = {
+                baseURL: basePath
+            }
+        }
+
+        if (maxTokens) obj.maxTokens = parseInt(maxTokens, 10)
+        if (topP) obj.topP = parseFloat(topP)
+        if (timeout) obj.timeout = parseInt(timeout, 10)
+        if (cache) obj.cache = cache
+        if (apiKey) obj.openAIApiKey = apiKey
+
+        const model = new ChatOpenAI(obj)
+
+        return model
+    }
+}
+
+module.exports = { nodeClass: ChatLitellm_ChatModels }