Attached EML files in emails sent via GMAIL-APIs are not viewable in GMAIL

1
votes

I am currently developing a gmail addon. The addon sends an email, with an attached eml file, to a particular recipient. Unfortunately, the recipient is not able to open the eml file attached with the email I sent via GMAIL API. If they click on the attached eml file they will receive the message "An error occurred while loading the attached message."

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I found two issues, which might be related to this issue, when I analyzed the data I saw when I clicked "show original" on the email. One is that all emails I sent via GMAIL API have the "Received from xxxxxxxxxxx named unknown by gmailapi.google.com with HTTPREST" header. And that the entire base64-encoded eml file is missing in the content of the email. Please see image below :

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Is this related to Emails sent via GMAIL API are flagged as Phishy? Or am I missing or doing something wrong? If I set the "attachment-type" to "text/plain" then the base64-encoded eml file data is present and viewable when I "show original" the email. Thank you all in advance.

1
gmailgmail-apigmail-addons
Do no worry about "Received from xxxxxxxxxxx named unknown by gmailapi.google.com with HTTPREST" for messages sent with Gmail API, this does not affect the readibility of the message. As for your encoding: Is your file base64-encoded or base64ur-encoded? – ziganotschka
Thank you @ziganotschka it is base64Encoded only. Do i need to use base64URLEncoded()?? thanks. – GovZ
Yes, it needs to be base64URLEncoded, see here: developers.google.com/gmail/api/v1/reference/users/messages/… – ziganotschka
I will try that too. But why does it work correctly if i set the eml-attachment content type as "text/plain" instead of "message/rfc822"? And, if i download the eml attachment sent with content-type="message/rfc822", the downloaded eml file is viewable perfectly in outlook. Another confusing case is the missing eml file content when i "show original". But if i set the attachment content-type to "text/plain" i can see the entire data when i "show original". If this were a simple case of encoding, downloading the eml file will not work too right? or am i mistaken? thanks. – GovZ
I am not familiar with eml files, but Gmail requires RFC 2822 formatting. Mind that RFC 2822 supersedes RFC 822 (or in other words: RFC 822 is outdated). tools.ietf.org/html/rfc2822 – ziganotschka

1 Answers

1
votes

@GovZ you can use MailApp.send rather than GmailApp.send, along with setting the content-type to "message/rfc822" and the email should preview correctly.

Details here: https://issuetracker.google.com/issues/155736170