ciss | ciss issue tracker | Stream Processing library

At first let me say that you did a good job in transferring data between web extension (Thunderbird add-on) and native application using native messaging. It isn't easy to understand it and set it up, but you managed to transfer required data with some tiny glitches you describe in your question.

... the resulting file contains double quotes (") at the start and the end of the file as well as escaped double quotes (\")

In the add-on you obtain raw email data as a string - console.log(typeof raw) gives string which you then pass to port.postMessage. Although the documentation says it takes JSON object representing the message to send, but it seems to accept single string value which is valid JSON according to some standards. In Delphi code you receive the message via STDIN and parse it using TJSONObject.ParseJSONValue into TJSONValue. It will in fact create instance of TJSONString. You can verify that by examining the value of jsonValue.ClassName. The problem with quotes arises when you use jsonValue.ToString which returns quoted version of the string that is basically the same what you had before parsing. Use the Value property to return raw string value.

Using jsonValue.Value alone will not help you with the encoding issue. The raw message data that you obtain from the e-mail client is in EML format. It conforms to RFC-822 and that means it is ASCII encoded, but it can contain arbitrarily encoded message parts (see your own sample EML). Since you only want to save EML file as is not taking any encoding into account, the best would be to transfer raw bytes of EML, but this isn't out-of-the-box supported by Javascript and native messaging API. Therefore I'd suggest you to send Base64-encoded data string to native application where you decode it into raw bytes that you can write straight to disk.

To encode raw message data as Base64 string in add-on use function btoa:

Your date column is in character format. This means that ggplot will by default convert it to a factor and arrange it in alphabetical order, which is why the plot appears in a different shape. One way to fix this is to ensure you have the levels in the correct order before plotting, like this:

Your code is saving only the last object in the list because you are creating and saving the object outside of the loop. Try this,

edit: While this will most likely solve the error you're getting, I agree with Edward's advice to use readxl::read_excel which should preserve the dates.

The problem with