Multipart/form-data Upload

Information
Description	Code snippet for fetching a pre-signed upload URL and uploading ZIP file using multipart/form-data.
Purpose	The function: Builds the pre-signed upload POST request Uploads the ZIP file as multipart/form-data
Language	Kotlin

Input Parameters

zipFile: File The ZIP file containing the JPG images.

uploadUrl: String The base S3 endpoint URL provided by the /request-url API endpoint. It is typically in the format of https://<bucket-name>.s3.amazonaws.com/.

fields: Map<String, String> This is a map of key-value pairs that must be included in the multipart request's form data.

Output

success: Boolean Value is true when the upload succeeded.

Snippet

import okhttp3.*
import java.io.File

fun uploadZipToPresignedUrl(zipFile: File, uploadUrl: String, fields: Map<String, String>): Boolean {
    val client = OkHttpClient()

    val multipartBodyBuilder = MultipartBody.Builder().setType(MultipartBody.FORM)

    // Add all required AWS fields
    for ((key, value) in fields) {
        multipartBodyBuilder.addFormDataPart(key, value)
    }

    // Add file as "file" field
    multipartBodyBuilder.addFormDataPart(
        "file", zipFile.name,
        RequestBody.create(MediaType.parse("application/zip"), zipFile)
    )

    val request = Request.Builder()
        .url(uploadUrl)
        .post(multipartBodyBuilder.build())
        .build()

    client.newCall(request).execute().use { response ->
        if (!response.isSuccessful) {
            println("Upload failed with code: ${response.code}")
            return false
        }

        return true
    }
}

Notes

The above code snippet was AI-generated and not yet tested on syntax or runtime errors. It merely serves as an example implementation. Be cautious when using this snippet.

It's important to add the AWS fields first and add the "file" key as latest.