How to use Nuxt 3 server as a passthrough API with FormData to hide external endpoints - api

Question

I'm trying to get my head around the Nuxt /server API and can't seem to figure out how to send a POST request with form-data (ie files) to Nuxt server to forward on to an external service:
In my pages.vue file I have this method:
async function onSubmit() {
const formData = new FormData();
for (let file of form.files) {
await formData.append("image", file);
}
await $fetch("/api/send", {
method: "POST",
body: formData
});
}
and then in /server/api/send.js I have:
export default defineEventHandler(async (event) => {
const { method } = event.node.req;
// I THINK THE ISSUE IS HERE
const body =
method !== "GET" && method !== "HEAD"
? await readMultipartFormData(event)
: undefined;
const response = await $fetch.raw(https://*******, {
method,
baseURL: *********,
headers: {
},
body: body
});
return response._data;
}
I'm effectively creating a passthrough API using Nuxt so that the external endpoint isn't exposed to the end user. Just can't figure out how to access the formData in the correct format to pass through on the server side. I don't think I am supposed to use readMultipartFormData() because that seems to be parsing the data somehow whereas I just want to pass the formData straight through to the external API. Any tips?
I've tried using both readMultipartFormData() and readBody() and neither seem to work. I don't actually need to read the body but rather get it and pass it through without any formatting...

Answer 1

If you want to pass the data with formdata to the endpoint try this library:
https://www.npmjs.com/package/object-to-formdata
code:
import { serialize } from 'object-to-formdata';
const formData = serialize(body);
const response = await $fetch.raw(https://*******, {
method,
baseURL: *********,
headers: {
},
body: formData
});

Answer 2

I managed to make it work with ugly solution, first you have to update nuxt to version 3.2.0 min then here my front side
let jobApplicationDTO = {
firstName: values.firstName,
lastName: values.lastName,
email: values.email,
phoneNumber: values.phoneNumber,
company: values.company,
shortDescription: values.shortDescription
};
const formData = new FormData();
formData.append("application", new Blob([JSON.stringify(jobApplicationDTO)], {type: "application/json"}));
formData.append("file", values.file) ;
//formData.append("file", values.file );
await useFetch("/api/application", {
method: "POST",
body: formData,
onResponse({request, response, options}) {
// Process the response data
if (response.status === 200) {
errorMessage.value = "";
successMessage.value = "Your application wa sent successfully, you will be contacted soon !";
}
},
onResponseError({request, response, options}) {
console.debug(response);
if (response.status === 400) {
successMessage.value = "";
errorMessage.value = "There may be an issue with our server. Please try again later, or send an email to support#mantiq.com";
} else {
successMessage.value = "";
errorMessage.value = "Sorry we couldn’t send the message, there may be an issue with our server. Please try again later, or send an email to support#mantiq.com";
}
},
});
}
and server side
import {FormData} from "node-fetch-native";
export default defineEventHandler(async (event) => {
const {BACKEND_REST_API, ENQUIRY_TOKEN} = useRuntimeConfig();
//retrieve frontend post formData
const form = await readMultipartFormData(event);
const applicationUrl = BACKEND_REST_API + '/job/apply'
console.log("url used for enquiry rest call :" + applicationUrl);
console.log("Job application token :" + ENQUIRY_TOKEN);
const formData = new FormData();
console.log(form);
if (form) {
formData.append(form[0].name, new Blob([JSON.stringify(JSON.parse(form[0].data))], {type: form[0].type}));
formData.append(form[1].name, new Blob([form[1].data], {type: form[1].type}), form[1].filename);
}
console.log(formData.values);
return await $fetch(applicationUrl, {
method: "POST",
body: formData,
headers: {
Authorization: ENQUIRY_TOKEN,
},
});
})
What is funny is on frontend you have to create a formData , then to get content and to recreate a formData from your previous formData converted in MultiFormPart[], i created a ticket on nuxt to see how to do it properly