How to fully export a html email with the gmail api in java

问题

I want to extract a specific spam mail with the gmail api and display it with my webapp but the styling is lost during the export. The problem is the styling is not provided inline and I can't find the source of the styling.

I am using spring boot and the gmail java api to extract the email. I tested some other emails that contain inline styling and they work. I extracted the html code of the email manually and tired display it via a html file but it only get's displayed without styling.


//How I get the message
Message message = service.users().messages().get(USER, messages.get(0).getId()).setFormat("full").execute();

//How I get the content
 private String getMessageContent(Message message) {
        StringBuilder stringBuilder = new StringBuilder();
        try {
            if(message.getPayload().getParts() != null) {
                handleEmailMainContent(message.getPayload().getParts(), stringBuilder);
                byte[] bodyBytes = Base64.decodeBase64(stringBuilder.toString());
                //System.out.println(new String(bodyBytes, "UTF-8"));
                String untrustedHTML = new String(bodyBytes, "UTF-8");
                // sanitize content before saving it
                System.out.println(untrustedHTML);
                return sanitizeContent(untrustedHTML);
            } else {
                return "";
            }
        } catch (UnsupportedEncodingException e) {
           System.out.println("UnsupportedEncoding: " + e.toString());
            return message.getSnippet();
        }
    }

    private void handleEmailMainContent(List<MessagePart> messageParts, StringBuilder stringBuilder) {
        for (MessagePart messagePart : messageParts) {
            switch (messagePart.getMimeType()) {
                case "text/plain":
                    handleMimeTypeTextPlain(messagePart, stringBuilder);
                    break;
                case "text/html":
                    handleMimeTypeTextHtml(messagePart, stringBuilder);
                    break;
                default:
                    break;
            }
        }
    }

private void handleMimeTypeTextPlain(MessagePart messagePart, StringBuilder stringBuilder) {
        stringBuilder.append(messagePart.getBody().getData());
        stringBuilder.append(System.lineSeparator());
    }

    private void handleMimeTypeTextHtml(MessagePart messagePart, StringBuilder stringBuilder) {
        stringBuilder.append(messagePart.getBody().getData());
        stringBuilder.append(System.lineSeparator());
    }

Snippet of what I extract (unsanitized)

[image: logo]
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I sanitize the html code for security reasons but I even tried the unsanitized version and had no success.

I would expect that I can extract everything I need through the gmail API to display the email like it get's displayed at my gmail client but the email lacks the needed styling.

来源：https://stackoverflow.com/questions/56257871/how-to-fully-export-a-html-email-with-the-gmail-api-in-java

标签

java

html-email

gmail-api