https://homeostasis.scs.carleton.ca/wiki/index.php?action=history&feed=atom&title=WebFund_2024F_Lecture_8 2026-05-12T20:54:40Z Revision history for this page on the wiki MediaWiki 1.42.1 https://homeostasis.scs.carleton.ca/wiki/index.php?title=WebFund_2024F_Lecture_8&diff=24770&oldid=prev 2024-10-03T21:26:35Z

<p>Created page with &quot;==Video== Video from the lecture for October 3, 2024 is now available: * [https://homeostasis.scs.carleton.ca/~soma/webfund-2024f/lectures/comp2406-2024f-lec08-20241003.m4v video] * [https://homeostasis.scs.carleton.ca/~soma/webfund-2024f/lectures/comp2406-2024f-lec08-20241003.cc.vtt auto-generated captions] ==Notes== &lt;pre&gt; Lecture 8 --------- Assignment 1 is due on Monday, Oct. 7th, will discuss solutions in class on Tuesday. If you ware working on Windows, you nee...&quot;</p> <p><b>New page</b></p><div>==Video==<br /> <br /> Video from the lecture for October 3, 2024 is now available:<br /> * [https://homeostasis.scs.carleton.ca/~soma/webfund-2024f/lectures/comp2406-2024f-lec08-20241003.m4v video]<br /> * [https://homeostasis.scs.carleton.ca/~soma/webfund-2024f/lectures/comp2406-2024f-lec08-20241003.cc.vtt auto-generated captions]<br /> <br /> ==Notes==<br /> <br /> &lt;pre&gt;<br /> Lecture 8<br /> ---------<br /> <br /> Assignment 1 is due on Monday, Oct. 7th, will discuss solutions in class on Tuesday.<br /> <br /> If you ware working on Windows, you need an editor that will produce UNIX-style text files. Most sane text editors will not change the type of file, so if you start with the template you should be fine.<br /> <br /> Newer versions of Notepad on Windows may have support for UNIX textfiles, not sure.<br /> <br /> TextEdit on Mac does support it, but its default format is RTF, so you have to tell it to save as a plain text file.<br /> - if you can change the font of individual words or lines, it isn&#039;t a plain text file<br /> <br /> When you are doing web development, you SHOULD be using UNIX-style text files.<br /> - DOS style text files will often work, but they can also cause weird issues<br /> - UNIX-style text files are basically always safe<br /> <br /> VSCode is a perfectly good text editor and should do the right thing.<br /> <br /> ONE IMPORTANT THING<br /> - openstack VMs may go down at any time!<br /> - make sure to keep local backups of any important work<br /> <br /> HOW SHOULD YOU BE DOING TUTORIALS?<br /> - your goal should be to understand every line of code that is assigned<br /> - to that end, you should do the suggested tasks<br /> - IN ADDITION, you should play with the code!<br /> - change, delete things<br /> - extend functionality<br /> <br /> The code in this class is mostly boilerplate-free, almost everything is significant<br /> - if you don&#039;t know why a line is there, you&#039;re probably missing a concept<br /> <br /> Normally, when we use a database in a web application, that database is separate from the web server.<br /> - often running on a completely different computer<br /> - communication is over the network, whether local or remote<br /> (as most local databases are still in separate processes<br /> and behave as if they were on a separate machine)<br /> <br /> But not with sqlite<br /> - it is an embedded database, becomes part of the application<br /> - it is VERY fast, sometimes faster than regular file I/O<br /> <br /> As a piece of software engineering, sqlite is a wonder<br /> - very small, very reliable, very efficient<br /> - all written in C with LOTS of tests<br /> - uses its own revision control system, Fossil, rather than git<br /> (guess what the file format of Fossil is?)<br /> <br /> But given that sqlite is written in C, but it isn&#039;t running as a separate process, how is it incorporated into our Deno program?<br /> - by using a version where the C has been compiled into WebAssembly<br /> <br /> <br /> So modern web browsers can execute code in two formats:<br /> - JavaScript<br /> - WebAssembly<br /> <br /> WebAssembly is designed as a target for compilers, so basically any code can be complied to WebAssembly and used in a browser<br /> - but that code will need some JavaScript glue code to use all of a browser&#039;s APIs<br /> <br /> <br /> Understand that sqlite isn&#039;t like other databases<br /> - expects only one program to access it at a time<br /> - generally fine if embedded, but you don&#039;t want to be having multiple<br /> threads accessing sqlite at the same time, could go badly<br /> - should NOT be shared between concurrent programs!<br /> - can be done to some degree, sqlite will lock the entire database<br /> - but definitely not the way to go<br /> <br /> In the context of Deno, this isn&#039;t a big deal<br /> - sqlite is so fast, can be part of main event loop<br /> - don&#039;t need to use it asynchronously<br /> - and in fact you really shouldn&#039;t try<br /> <br /> In JavaScript, =&gt; is used to declare inline anonymous functions<br /> - specifically, you have parentheses with the function arguments,<br /> =&gt;, and then {} for the function body<br /> &lt;/pre&gt;</div>

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