Create Draft Email

import * as wmill from "windmill-client"

import { S3Object } from "windmill-client"

/**

 * Create Draft Email

 * Create a draft in the Drafts folder, with optional recipients and file attachments from object storage (about 3 MB in total). Returns the draft message; send it with Send Draft. Requires Mail.ReadWrite (a connection default).

 */

export async function main(

  auth: RT.MsOutlook,

  subject: string,

  body: string,

  content_type: "HTML" | "Text" = "HTML",

  to: string[] | undefined,

  cc: string[] | undefined,

  bcc: string[] | undefined,

  attachments: S3Object[] | undefined,

  mailbox: string | undefined

) {

  const base = `https://graph.microsoft.com/v1.0/${

    mailbox != null && mailbox !== ""

      ? `users/${encodeURIComponent(mailbox)}`

      : "me"

  }`

  const recipients = (addresses: string[] | undefined) =>

    (addresses ?? [])

      .filter((a) => a != null && a.trim() !== "")

      .map((address) => ({ emailAddress: { address } }))

  const files = []

  for (const file of attachments ?? []) {

    const bytes = await wmill.loadS3File(file)

    if (!bytes) throw new Error(`Could not load ${file.s3}`)

    files.push({

      "@odata.type": "#microsoft.graph.fileAttachment",

      name: file.s3.split("/").pop(),

      contentBytes: Buffer.from(bytes).toString("base64"),

    })

  }

  const response = await fetch(`${base}/messages`, {

    method: "POST",

    headers: {

      Authorization: `Bearer ${auth.token}`,

      "Content-Type": "application/json",

      Accept: "application/json",

    },

    body: JSON.stringify({

      subject,

      body: { contentType: content_type, content: body },

      toRecipients: recipients(to),

      ccRecipients: recipients(cc),

      bccRecipients: recipients(bcc),

      attachments: files,

    }),

  })

  if (!response.ok) {

    throw new Error(`${response.status} ${await response.text()}`)

  }

  return await response.json()

}