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fix: Support other encoding than UTF-8 #131

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fix: Support other encoding than UTF-8 #131

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4288c67
fix: Support other encoding than UTF-8
amertak Mar 23, 2021
75abd79
chore: handle body/header text/any
amertak Mar 25, 2021
d0e3440
refactor: reuse regex and replacement text
amertak Mar 25, 2021
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32 changes: 31 additions & 1 deletion index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@

var AWS = require('aws-sdk');

/*global TextDecoder */

console.log("AWS Lambda SES Forwarder // @arithmetric // Version 5.0.0");

// Configure the S3 bucket and key prefix for stored raw emails, and the
Expand Down Expand Up @@ -195,7 +197,28 @@ exports.fetchMessage = function(data) {
return reject(
new Error("Error: Failed to load message body from S3."));
}
data.emailData = result.Body.toString();

const naivelyReadBody = result.Body.toString();
const encodingMatches = naivelyReadBody.match(/text\/plain;\s*charset=([^;]+);/);
if (encodingMatches) {
try {
const encoding = encodingMatches[1]
const textDecoder = new TextDecoder(encoding);

data.emailData = textDecoder.decode(result.Body)
} catch (err) {
data.log({
level: "error",
message: "Could not decode body with desired encoding, fallback for naively read body.",
error: err,
stack: err.stack
});
data.emailData = naivelyReadBody;
}
} else {
data.emailData = naivelyReadBody;
}

return resolve(data);
});
});
Expand Down Expand Up @@ -274,6 +297,13 @@ exports.processMessage = function(data) {
// Remove Message-ID header.
header = header.replace(/^message-id:[\t ]?(.*)\r?\n/mgi, '');

const charsetRegex = /content-type:\s*text\/([^;]+);\s*charset=([^;\s]+)/gi
const replacementText = 'Content-Type: text/$1; charset=UTF-8'

// JS only supports UTF-8 kinda, we also converted the text of the email into UTF8 in fetchMessage function
header = header.replace(charsetRegex, replacementText)
body = body.replace(charsetRegex, replacementText)

// Remove all DKIM-Signature headers to prevent triggering an
// "InvalidParameterValue: Duplicate header 'DKIM-Signature'" error.
// These signatures will likely be invalid anyways, since the From
Expand Down