api/server/middleware/buildEndpointOption.js

const { parseConvo, EModelEndpoint } = require('librechat-data-provider');
const { getModelsConfig } = require('~/server/controllers/ModelController');
const azureAssistants = require('~/server/services/Endpoints/azureAssistants');
const assistants = require('~/server/services/Endpoints/assistants');
const gptPlugins = require('~/server/services/Endpoints/gptPlugins');
const { processFiles } = require('~/server/services/Files/process');
const anthropic = require('~/server/services/Endpoints/anthropic');
const openAI = require('~/server/services/Endpoints/openAI');
const custom = require('~/server/services/Endpoints/custom');
const google = require('~/server/services/Endpoints/google');
const enforceModelSpec = require('./enforceModelSpec');
const { handleError } = require('~/server/utils');

const buildFunction = {
  [EModelEndpoint.openAI]: openAI.buildOptions,
  [EModelEndpoint.google]: google.buildOptions,
  [EModelEndpoint.custom]: custom.buildOptions,
  [EModelEndpoint.azureOpenAI]: openAI.buildOptions,
  [EModelEndpoint.anthropic]: anthropic.buildOptions,
  [EModelEndpoint.gptPlugins]: gptPlugins.buildOptions,
  [EModelEndpoint.assistants]: assistants.buildOptions,
  [EModelEndpoint.azureAssistants]: azureAssistants.buildOptions,
};

async function buildEndpointOption(req, res, next) {
  const { endpoint, endpointType } = req.body;
  const parsedBody = parseConvo({ endpoint, endpointType, conversation: req.body });

  if (req.app.locals.modelSpecs?.list && req.app.locals.modelSpecs?.enforce) {
    /** @type {{ list: TModelSpec[] }}*/
    const { list } = req.app.locals.modelSpecs;
    const { spec } = parsedBody;

    if (!spec) {
      return handleError(res, { text: 'No model spec selected' });
    }

    const currentModelSpec = list.find((s) => s.name === spec);
    if (!currentModelSpec) {
      return handleError(res, { text: 'Invalid model spec' });
    }

    if (endpoint !== currentModelSpec.preset.endpoint) {
      return handleError(res, { text: 'Model spec mismatch' });
    }

    if (
      currentModelSpec.preset.endpoint !== EModelEndpoint.gptPlugins &&
      currentModelSpec.preset.tools
    ) {
      return handleError(res, {
        text: `Only the "${EModelEndpoint.gptPlugins}" endpoint can have tools defined in the preset`,
      });
    }

    const isValidModelSpec = enforceModelSpec(currentModelSpec, parsedBody);
    if (!isValidModelSpec) {
      return handleError(res, { text: 'Model spec mismatch' });
    }
  }

  req.body.endpointOption = buildFunction[endpointType ?? endpoint](
    endpoint,
    parsedBody,
    endpointType,
  );

  const modelsConfig = await getModelsConfig(req);
  req.body.endpointOption.modelsConfig = modelsConfig;

  if (req.body.files) {
    // hold the promise
    req.body.endpointOption.attachments = processFiles(req.body.files);
  }
  next();
}

module.exports = buildEndpointOption;