| 1 | import { HumanMessage, type BaseMessage } from "@langchain/core/messages"; |
| 2 | import { createMiddleware } from "langchain"; |
| 3 | |
| 4 | interface PastedContentItem { |
| 5 | id: string; |
| 6 | content: string; |
| 7 | startIndex: number; |
| 8 | } |
| 9 | |
| 10 | function buildEnhancedContent( |
| 11 | originalContent: string, |
| 12 | pastedContent: PastedContentItem[], |
| 13 | ): string { |
| 14 | const sorted = [...pastedContent].sort((a, b) => b.startIndex - a.startIndex); |
| 15 | |
| 16 | let result = originalContent; |
| 17 | |
| 18 | for (const item of sorted) { |
| 19 | const insertPosition = Math.min(item.startIndex, result.length); |
| 20 | const pastedTag = `\n${item.content}\n`; |
| 21 | |
| 22 | result = |
| 23 | result.slice(0, insertPosition) + |
| 24 | pastedTag + |
| 25 | result.slice(insertPosition); |
| 26 | } |
| 27 | |
| 28 | return result; |
| 29 | } |
| 30 | |
| 31 | export const pastedContentMiddleware = createMiddleware({ |
| 32 | name: "ProcessPastedContent", |
| 33 | wrapModelCall: async (request, handler) => { |
| 34 | const processedMessages = request.messages.map((message) => { |
| 35 | if (message.type !== "human") { |
| 36 | return message; |
| 37 | } |
| 38 | |
| 39 | const pastedContent = message.additional_kwargs?.pastedContent as |
| 40 | | PastedContentItem[] |
| 41 | | undefined; |
| 42 | |
| 43 | if (!pastedContent || pastedContent.length === 0) { |
| 44 | return message; |
| 45 | } |
| 46 | |
| 47 | const originalContent = |
| 48 | typeof message.content === "string" |
| 49 | ? message.content |
| 50 | : Array.isArray(message.content) |
| 51 | ? message.content |
| 52 | .filter((part) => typeof part === "object" && part.type === "text") |
| 53 | .map((part) => ("text" in part ? part.text ?? "" : "")) |
| 54 | .join("\n") |
| 55 | : ""; |
| 56 | |
| 57 | return new HumanMessage({ |
| 58 | content: buildEnhancedContent(originalContent, pastedContent), |
| 59 | id: message.id, |
| 60 | response_metadata: message.response_metadata, |
| 61 | additional_kwargs: { |
| 62 | ...message.additional_kwargs, |
| 63 | pastedContentProcessed: true, |
| 64 | }, |
| 65 | }); |
| 66 | }); |
| 67 | |
| 68 | return handler({ |
| 69 | ...request, |
| 70 | messages: processedMessages, |
| 71 | }); |
| 72 | }, |
| 73 | }); |
| 74 | |
| 75 | export function processPastedContent(messages: BaseMessage[]): BaseMessage[] { |
| 76 | return messages.map((message) => { |
| 77 | if (message.type !== "human") { |
| 78 | return message; |
| 79 | } |
| 80 | |
| 81 | const pastedContent = message.additional_kwargs?.pastedContent as |
| 82 | | PastedContentItem[] |
| 83 | | undefined; |
| 84 | |
| 85 | if (!pastedContent || pastedContent.length === 0) { |
| 86 | return message; |
| 87 | } |
| 88 | |
| 89 | const originalContent = |
| 90 | typeof message.content === "string" |
| 91 | ? message.content |
| 92 | : Array.isArray(message.content) |
| 93 | ? message.content |
| 94 | .filter((part) => typeof part === "object" && part.type === "text") |
| 95 | .map((part) => ("text" in part ? part.text ?? "" : "")) |
| 96 | .join("\n") |
| 97 | : ""; |
| 98 | |
| 99 | return new HumanMessage({ |
| 100 | content: buildEnhancedContent(originalContent, pastedContent), |
| 101 | id: message.id, |
| 102 | response_metadata: message.response_metadata, |
| 103 | additional_kwargs: { |
| 104 | ...message.additional_kwargs, |
| 105 | pastedContentProcessed: true, |
| 106 | }, |
| 107 | }); |
| 108 | }); |
| 109 | } |
| 110 |