[TangerineSDR] Webserver for local host

Tue Dec 3 16:26:22 EST 2019

Hi Bill,

I don’t think a virtual environment is necessary. To run flask in a production environment, I believe you can run it as a module in apache. See https://www.codementor.io/abhishake/minimal-apache-configuration-for-deploying-a-flask-app-ubuntu-18-04-phu50a7ft

73 de Nathaniel W2NAF

From: TangerineSDR <tangerinesdr-bounces at lists.tapr.org> on behalf of TangerineSDR Listserv <tangerinesdr at lists.tapr.org>
Reply-To: TangerineSDR Listserv <tangerinesdr at lists.tapr.org>
Date: Tuesday, December 3, 2019 at 2:35 PM
To: "Markowitz, Evan" <em328 at njit.edu>
Cc: "Engelke, Bill" <bill.engelke at ua.edu>, TangerineSDR Listserv <tangerinesdr at lists.tapr.org>, David Witten <wittend at wwrinc.com>
Subject: Re: [TangerineSDR] Webserver for local host

Evan –
I’m looking thru some of the “getting started” items on the web about Flask, and hoping you can enlighten me on a couple of things –

  *   It seems that Flask is often used in a container (i.e., venv).  How important is it to do this? Seems like an unnecessary complication for our application, especially if we are going to standardize on Python 3.
  *   Documentation indicates (indeed, Flask itself gives a warning) that Flask (by itself) should not be run as a server “in a production environment.” The advice is to run it under the control of a production WSGI such as Waitress (in fact, running under a venv).  Do we need to plan to do this?
-73- Bill

From: Markowitz, Evan <em328 at njit.edu>
Sent: Tuesday, December 3, 2019 12:49 PM
To: Engelke, Bill <bill.engelke at ua.edu>
Cc: David Witten <wittend at wwrinc.com>; tangerinesdr at lists.tapr.org
Subject: Re: [TangerineSDR] Webserver for local host

Hi Bill,

Flask supports Python 3.5+, and I've used it across all of those versions up to and including 3.8 with no problem.

If we can, I'd love to be exclusive to Python 3 as, like you mentioned, Python 2 is going to be unsupported in less than a month anyway.

Thanks,
Evan

On Tue, Dec 3, 2019, 1:39 PM Engelke, Bill <bill.engelke at ua.edu<mailto:bill.engelke at ua.edu>> wrote:
Hello Dave & Evan –
Let’s gravitate toward Python then.  The framework that Evan mentioned (Flask) does seem to be of a lightweight variety, and should allow us to implement all the screens we need for controlling the TangerineSDR.  (I have attached the latest version of the Detailed Design for what is planned to run in the SBC for review and comment.  My idea is to implement all the web screens in the spec using whatever framework we pick).

One question, to try and avoid “interdependency hell” – the latest GNUradio runs well with Python V3.6.9. (I’m hoping we can avoid using Python2, as I have seen a continuous feed of warnings that support is phasing out).   I hope that Flask plays nice with Python3 (??)

All feedback is most welcome… 73- Bill AB4EJ

From: David Witten <wittend at wwrinc.com<mailto:wittend at wwrinc.com>>
Sent: Tuesday, December 3, 2019 12:17 PM
To: Engelke, Bill <bill.engelke at ua.edu<mailto:bill.engelke at ua.edu>>; Evan <em328 at njit.edu<mailto:em328 at njit.edu>>; tangerinesdr at lists.tapr.org<mailto:tangerinesdr at lists.tapr.org>
Subject: Re: [TangerineSDR] Webserver for local host

The power of the board is not really the issue for me.

There are SO many options!

I dislike Tomcat and Java-based solutions for many reasons.  I have seen many supposedly 'Open' projects fail  or just limp along due to poor choice of implementation language. Much of the good SDR software available is crippled by dependence on non-portable code and dependence on proprietary environments such as whatever Microsoft calls dot.net<http://dot.net> this week.  Java is a similar island in a world of alternatives.

You can't keep everyone happy, but the single-board world seems heavily oriented towards Python these days.

The services need to be coded completely in an Open Source environment that is being taught to end users.  There is no need to squander CPU resources and no reason to alienate future maintainers.  You can probably write a five line web server in COBOL these days.  But who wants to? How do you keep it standards-compliant and secure?

I have a long list of personal likes and dislikes of course.  I'm cranky and old.  But some combinations (language + open libraries + user familiarity) stand out:

#1 Python - provides: portability, libraries to talk to hardware, extremely large user base and battle hardened framework support.
#2 node.js - advantages similar to Python, simpler interaction with client-side code (javascript both ends) and efficient low level services.
#3 go / golang - similar to the above, more rigorous language implementation, designed for this type of work, but less well known.
#4 lightweight Web servers such as civetweb (one of many)  One example: https://github.com/civetweb/civetweb - many features, lightweight.
#5 full blown standard web servers: Nginx<https://www.nginx.com/resources/wiki/>, Apache<https://www.apachelounge.com/> + really almost any backend (except Java) - overkill, but extremely well supported, available in any distro, intense security maintenance.

I do not see much need for complication with more than very lightweight 'frameworks'.

I would propose an architecture where the localhost runs a simple web service loop.  This loop would be launched at boot and principally serve  two pages - one page that just provides status information without authentication.  The other would be a page requiring login by the owner/controller of the localhost that allows control of services and presentation of data to the owner/controller of the device.  All data would be served over secure, certificated connections.  All interaction would be through small, purpose-built service handlers that autostart but allow management through the owner/controller's page.

In many cases, such as the transfer of bulk data to the central repository, connections would be best handled using Web Sockets or some similar mechanism directly by the service process with only lightweight progress reporting directed through the Web interface.

These are just my thoughts right now, I'm sure that I can come up with more opinions if anyone wants to hear them.

Dave Witten, KD0EAG

On Tue, Dec 3, 2019 at 11:10 AM Engelke, Bill <bill.engelke at ua.edu<mailto:bill.engelke at ua.edu>> wrote:
Dave – well, my testing has shown the Odroid to have the processing capability of a typical modern desktop (as opposed to a typical SBC like the Raspberry). Be that as it may, could you make a suggestion or two on what to use instead?   -73- Bill

From: TangerineSDR <tangerinesdr-bounces at lists.tapr.org<mailto:tangerinesdr-bounces at lists.tapr.org>> On Behalf Of David Witten via TangerineSDR
Sent: Tuesday, December 3, 2019 10:41 AM
To: tangerinesdr at lists.tapr.org<mailto:tangerinesdr at lists.tapr.org>
Cc: David Witten <wittend at wwrinc.com<mailto:wittend at wwrinc.com>>
Subject: [TangerineSDR] Webserver for local host

All concerned,

I deeply oppose the use of tomcat and any form of java-based services on the local host.  I will not be writing any code to support the use of Java, JSP, or Mono on single-board computers.  Almost any other toolset will do.  These are tools rarely used in the single-board computer world.  They may be suitable for banks and corporate monoliths (or not!), but not for small systems.

Dave Witten, KD0EAG
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