@n8n/n8n-nodes-langchain
Version:
129 lines • 6.49 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.N8nStructuredOutputParser = void 0;
const output_parsers_1 = require("@langchain/classic/output_parsers");
const get_1 = __importDefault(require("lodash/get"));
const n8n_workflow_1 = require("n8n-workflow");
const zod_1 = require("zod");
const ai_utilities_1 = require("@n8n/ai-utilities");
const helpers_1 = require("../helpers");
const STRUCTURED_OUTPUT_KEY = '__structured__output';
const STRUCTURED_OUTPUT_OBJECT_KEY = '__structured__output__object';
const STRUCTURED_OUTPUT_ARRAY_KEY = '__structured__output__array';
class N8nStructuredOutputParser extends output_parsers_1.StructuredOutputParser {
constructor(context, zodSchema) {
super(zodSchema);
this.context = context;
this.lc_namespace = ['langchain', 'output_parsers', 'structured'];
}
async parse(text, _callbacks, errorMapper) {
const { index } = this.context.addInputData(n8n_workflow_1.NodeConnectionTypes.AiOutputParser, [
[{ json: { action: 'parse', text } }],
]);
try {
let jsonString = text.trim();
const lines = jsonString.split('\n');
let fenceStartIndex = -1;
let fenceEndIndex = -1;
for (let i = 0; i < lines.length; i++) {
const trimmedLine = lines[i].trim();
if (fenceStartIndex === -1 && trimmedLine.match(/^```(?:json)?$/)) {
fenceStartIndex = i;
}
else if (fenceStartIndex !== -1 && trimmedLine === '```') {
fenceEndIndex = i;
break;
}
}
if (fenceStartIndex !== -1 && fenceEndIndex !== -1) {
jsonString = lines.slice(fenceStartIndex + 1, fenceEndIndex).join('\n');
}
const json = JSON.parse(jsonString.trim());
const parsed = await this.schema.parseAsync(json);
let result = ((0, get_1.default)(parsed, [STRUCTURED_OUTPUT_KEY, STRUCTURED_OUTPUT_OBJECT_KEY]) ??
(0, get_1.default)(parsed, [STRUCTURED_OUTPUT_KEY, STRUCTURED_OUTPUT_ARRAY_KEY]) ??
(0, get_1.default)(parsed, STRUCTURED_OUTPUT_KEY) ??
parsed);
result = (0, helpers_1.unwrapNestedOutput)(result);
(0, ai_utilities_1.logAiEvent)(this.context, 'ai-output-parsed', { text, response: result });
this.context.addOutputData(n8n_workflow_1.NodeConnectionTypes.AiOutputParser, index, [
[{ json: { action: 'parse', response: result } }],
]);
return result;
}
catch (e) {
const isEmptyOutput = (typeof text === 'string' && text.trim() === '{}') ||
(e instanceof zod_1.z.ZodError &&
e.issues?.[0] &&
e.issues?.[0].code === 'invalid_type' &&
e.issues?.[0].path?.[0] === 'output' &&
e.issues?.[0].expected === 'object' &&
e.issues?.[0].received === 'undefined');
const nodeError = new n8n_workflow_1.NodeOperationError(this.context.getNode(), isEmptyOutput
? 'The AI model returned an empty response to the Structured Output Parser'
: "Model output doesn't fit required format", {
description: isEmptyOutput
? "This usually happens when the model runs out of tokens before it can generate the structured output. Try reducing the prompt length, increasing the model's max output tokens, or simplifying the output schema. To continue the execution when this happens, change the 'On Error' parameter in the root node's settings."
: "To continue the execution when this happens, change the 'On Error' parameter in the root node's settings",
});
if (e instanceof SyntaxError) {
nodeError.context.outputParserFailReason = 'Invalid JSON in model output';
}
else if (isEmptyOutput) {
nodeError.context.outputParserFailReason = 'Model output wrapper is an empty object';
}
else if (e instanceof zod_1.z.ZodError) {
nodeError.context.outputParserFailReason =
'Model output does not match the expected schema';
}
(0, ai_utilities_1.logAiEvent)(this.context, 'ai-output-parsed', {
text,
response: e.message ?? e,
});
this.context.addOutputData(n8n_workflow_1.NodeConnectionTypes.AiOutputParser, index, nodeError);
if (errorMapper) {
throw errorMapper(e);
}
throw nodeError;
}
}
static async fromZodJsonSchema(zodSchema, nodeVersion, context) {
let returnSchema;
if (nodeVersion === 1) {
returnSchema = zod_1.z.object({
[STRUCTURED_OUTPUT_KEY]: zod_1.z
.object({
[STRUCTURED_OUTPUT_OBJECT_KEY]: zodSchema.optional(),
[STRUCTURED_OUTPUT_ARRAY_KEY]: zod_1.z.array(zodSchema).optional(),
})
.describe(`Wrapper around the output data. It can only contain ${STRUCTURED_OUTPUT_OBJECT_KEY} or ${STRUCTURED_OUTPUT_ARRAY_KEY} but never both.`)
.refine((data) => {
return (Boolean(data[STRUCTURED_OUTPUT_OBJECT_KEY]) !==
Boolean(data[STRUCTURED_OUTPUT_ARRAY_KEY]));
}, {
message: 'One and only one of __structured__output__object and __structured__output__array should be present.',
path: [STRUCTURED_OUTPUT_KEY],
}),
});
}
else if (nodeVersion < 1.3) {
returnSchema = zod_1.z.object({
output: zodSchema.optional(),
});
}
else {
returnSchema = zod_1.z.object({
output: zodSchema,
});
}
return new N8nStructuredOutputParser(context, returnSchema);
}
getSchema() {
return this.schema;
}
}
exports.N8nStructuredOutputParser = N8nStructuredOutputParser;
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