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sTunnel for modern email protocols in old email clients


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5 hours ago, Mathwiz said:

So lots of little problems, but I think #1 is the important one since it's the one that seems to be slowing everything down.

Thanks so much for the extremely detailed explanation. :) Unfortunately, I can’t tell anything about IE8, but I found information about security patches for Eudora 7.1 from https://www.computerhistory.org/atchm/the-eudora-email-client-source-code/#comment-4302840899
Have you tried using it? And all that concerns the filtering of any content can be done using a bunch of ProxHTTPSProxyMII + Privoxy.

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The problem with Eudora has to do with the processing of css code (in this case, the e-mails from Sky), which almost brings Eudora to a standstill. This causes the HTTPSProxy to disconnect some connections again, which in turn leads to long load times, especially for Marks and Spencer (e-mail loads many resources). But to get the e-mails from Sky displayed correctly, I recommend Thunderbird (last running version under Windows XP 52.9.1). Although these long load times do not exist on Outlook Express and Windows Live Mail, they both work with the viewer through IE, so e-mails with up-to-date HTML code are no longer displayed correctly. The file "OriginalSource.htm" I downloaded from the forum and opened with Google Chrome without problems and correct representation.

Because of the fuzzy font in Thunderbird (version 52.9.1). Under Tools > Settings > Advanced > Edit configuration, search for the entry gfx.content.azure.backends and change it from "direct2d1.1, skia, cairo" to "direct2d1.1, cairo" (remove skia).

:)

Edited by heinoganda
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Thanks @heinogandaas always.
If you're correct, (and you always are! :worship:) then there is no solution to this other than to use another e-mail client.
Basically, Eudora can no longer cope with some modern e-mail messages, which is a PITA, but I suppose was inevitable with a program that hasn't been updated since 2006!
I'll stick with it for the moment, there are only two regular sources of messages that I receive from which cause the problem, but if it starts affecting more and more messages I will eventually have to review things. The vast majority do still display fine and immediately at the moment.
You can actually tell the Sky forum to send plain text instead of HTML, so that is one workaround, although the messages then look awful!
I can still just switch to Eudora's own viewer as well, where they still don't look good, but not as bad as sending plain text at source!
It still seems strange to me that Eudora can display the messages immediately with its own internal viewer, but can't using the embedded IE viewer option, and the fault seems to be in Eudora itself, and not in IE!
Thanks everyone else of course for your input into this, especially @Mathwiz.
If anyone else has any brainwaves as to how to work around this I would love to hear them!
Cheers, Dave.
:)
 

Edited by Dave-H
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4 hours ago, Dave-H said:

Eudora can display the messages immediately with its own internal viewer, but can't using the embedded IE viewer option, and the fault seems to be in Eudora itself, and not in IE!

Actually I think the fault is in neither Eudora nor IE, but in the email!

When I open your original email file in IE8, it does display quickly, but if you look at the bottom, there's a "progress bar" showing that it's still trying to download "something." Eventually that process times out, and the font changes somewhat (apparently from Arial to Sky's font). It looks to me like the difference is simply that Eudora waits for IE8's engine to finish rendering the file before it displays it, while IE8 itself displays a "draft" while it waits. It's probably a rather minor difference in how Eudora and IE8 call mshtml.dll (the Trident rendering engine).

In the original (unedited) email, there's a second style sheet at the bottom that contains protocol-relative URLs: an @import rule to bring in toolkit.css (which is redundant because it was brought in at the top of the email already), and two @font-face rules that try to download the font files (which are also redundant because toolkit.css already does that). This second style sheet is thus totally redundant and unnecessary, but it appears to be where IE and (probably) Eudora run into trouble.

The problem is, the email file was loaded from disk, not downloaded from the Internet, so the protocol IE tries to use is "file://".

I (finally) found an explanation of what's going on at Wikipedia. Most of us have seen the file: protocol used with three slashes, to load a file from our own PC into the browser. But there's another, seldom-used variation: "file://hostname/share/path/to/file". The protocol-relative URLs get turned into this variation, so IE interprets www.sky.com and helpforum.sky.com as local network hosts and tries to download files from them using SMB or some such instead of https:. (I suspected this was what was happening last night, but wasn't sure until I did a lot more research today.)

The good news is that protocol-relative URLs should become less common as https: becomes more and more standard for all web requests. There's less and less need for URLs that will work with either http: or https:. So I don't think you'll see this problem get worse over time.

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14 hours ago, Dave-H said:

If anyone else has any brainwaves as to how to work around this I would love to hear them!

You've got two suggestions already, which seem to have passed below the radar: Privoxy or Proxomitron.
Perhaps there may even be another simpler filter proxy to do the job, but we do know that HTTPSProxy does work with Proxomitron or Privoxy... so that this may be a start for a good workaround (not a solution, but no real solution seems possible ATM).

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Yes indeed, I forgot about that. :blushing:
You said it was a sledgehammer to crack a nut! :lol:
I actually do have Proxomitron already installed, I cannot for the life of me remember why, but I've had it on the system for years!
It's version "Naoko 4.5 (2003-6-1)" which I guess must be pretty out of date now.
I can't remember how to use it either, but I'll give it a go if it might help!
:)

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1 hour ago, Dave-H said:

You said it was a sledgehammer to crack a nut!

And that it sure is! :D
But it may be the best workaround more-or-less readly available.
Proxomitron is a very versatile filter proxy, so that it can filter any offending html code before it reaches the browser (er... in you case that'd be Eudora, of course!). So, the part you have to solve is how to insert Proxomitron in your proxy chain, just for Eudora (I bet @heinoganda can help you with this part) and how to program Proxomitron for it to filter what you want to filter (it should be via a script or a config file, of course) and maybe how to disable some potencially annoying extra paranoid default normally used by Proxomitron. I cannot help much because I've never used Proxomitron, till now (although I suspect I'll need it sooner or later). We have some Proxomitron users here at MSFN, who I'm sure will be glad to help. It's a pity owr own resident specialist in it (@herbalist) seems not to be around anymore...

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I realize we've gotten rather OT, but I can't help one more observation: Proxomitron and ProxHTTPSProxyMII may see a resurgence among Chromium users (Chrome, Edge, etc.) if Google follows through on their plans to cripple uBlock Origin and similar ad-blocking add-ons.

Hey, Google:

Quote

You shove ads in my face - big disgrace - somebody better put you back into your place!

We will, we will, block you! :D

(Apologies to Queen)

Anyhow, back to the question at hand: my original thought was to use Proxomitron to intercept the download of sky.net's toolkit.css and redirect it to a "fixed" version that would load the correct fonts. (I even figured out how to fix the .css myself!) But now I doubt it'll solve @Dave-H's original problem (long delays before the emails appear), because I'm pretty sure it only intercepts http: (and https:, with the help of ProxHTTPSProxyMII) requests, not the UNC network requests those emails cause Trident to attempt.

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35 minutes ago, Mathwiz said:

not the UNC network requests those emails cause Trident to attempt.

Well, if that's the case, it's more complicated than I initially thought. We'll have to find or make something that does filter UNC requests. :dubbio:

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This is all starting to sound very complicated and difficult.
However, as an exercise it will be fascinating to try!
I'm afraid it's all getting a bit over my head though.
:(
Is this off-topic for this thread?
As the thread was started about making old legacy e-mail clients (like Eudora) work with modern messages, I think it's probably OK.
I'm happy to start a new thread specifically for this problem if necessary.
Den?
:dubbio:

Edited by Dave-H
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6 hours ago, Dave-H said:

Is this off-topic for this thread?

IMO, no. Eudora is one of the best (if not the very best) stand-alone e-mail client ever. So, now that we have a diagnostic of the problem, at last, it seems proper to pursue the actual solution in the same thread.

6 hours ago, Dave-H said:

I'm afraid it's all getting a bit over my head though.

Me, too. But if @jumper is willing to try and create a standalone wrapper library to be dropped in Eudora's folder (even if some local executables will have to be hexedited to redirect some calls to the wrapper) he sure has the expertise to do so. I think we should go for it.

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The following code from Sky's e-mails uses Web Open Font Format (woff file), which is only supported as of IE9 and ensures long loading times. 

<style type="text/css">@import "//helpforum.sky.com/html/assets/toolkit.css";@font-face{font-family: "Sky Text"; src: url("//www.sky.com/assets/fonts/sky-regular.woff") format("woff")}@font-face{font-family: "Sky Text"; src: url("//www.sky.com/assets/fonts/sky-medium.woff") format("woff"); font-weight: bold}html, body, #MessageContainer{font-family: 'Sky Text', Arial;margin: 0;padding: 0;box-sizing: border-box;filter: progid: DXImageTransform.Microsoft.gradient(startColorstr="#c9c7d1", endColorstLOGNULL NowTransReader::ReadIt() JJFileMT::Truncate(122991)
r="#fefefe", GradientType=1);background-image: -webkit-linear-gradient(left, #c9c7d1 0%, #e5e5ea 6%, #fefefe 20%, #fefefe 80%, #e5e5ea 94%, #c9c7d1 100%);background-image: -moz-linear-gradient(left, #c9c7d1 0%, #e5e5ea 6%, #fefefe 20%, #fefefe 80%, #e5e5ea 94%, #c9c7d1 100%);background-image: -o-linear-gradient(left, #c9c7d1 0%, #e5e5ea 6%, #fefefe 20%, #fefefe 80%, #e5e5ea 94%, #c9c7d1 100%);background-image: linear-gradient(to right, #c9c7d1 0%, #e5e5ea 6%, #fefefe 20%, #fefefe 80%, #e5e5ea 94%, #c9c7d1 100%);}.header-row{padding: 10px; -webkit-box-shadow: 0 1px 10px 0 rgba(0, 0, 0, 0.2); -moz-box-shadow: 0 1px 10px 0 rgba(0, 0, 0, 0.2);box-shadow: 0 1px 10px 0 rgba(0, 0, 0, .2);background-color: #fff;}<!--if[mso]>.footer-links table{float: left; width: auto !important;}<![end if]-->.footer-links table{float: left; width: auto !important;}.footer-links a:link, .footer-links a:visited, .footer-links a:active, .footer-links a:hover{font-size: 18px;}

For e-mail programs such as Outlook Express and Windows Live Mail, where the Microsoft Viewer (IE) is used for viewing e-mails, the reloading of fonts can be prevented. At Eudora, I do not have this option, a suitable plugin for Eudora could provide a remedy, similar to an ad blocker where the code for reloading Web Open Font Format is removed. With the internal viewer of Eudora (HTML mails have problems with the reloading of pictures etc. with encrypted web server) there is no possibility to take over the proxy settings from the system (no use of HTTPSProxy possible), therefore the detour over the Microsoft Viewer (IE).

:)

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So if Sky are now using a font for their forum notification messages which isn't supported by IE in Windows XP, presumably it's causing a long delay but eventually it falls back to something else and the message then displays?
:dubbio:

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