LineDashedMaterial in three.js

To use LineDashedMaterial in three.js:

var geometry = new THREE.Geometry();
geometry.vertices.push(new THREE.Vector3(590058.52, 231354.16, 766.42));
geometry.vertices.push(new THREE.Vector3(589941.68, 231476.67, 736.52));
geometry.vertices.push(new THREE.Vector3(589781.32, 231491.91, 757.73));
geometry.vertices.push(new THREE.Vector3(589711.88, 231445.56, 768.16));
geometry.vertices.push(new THREE.Vector3(589702.04, 231336.49, 772.91));
geometry.computeLineDistances();

let material = new THREE.LineDashedMaterial( {
    color: 0xff0000,
    linewidth: 1,
    scale: 1,
    dashSize: 5,
    gapSize: 3,
} );

let line = new THREE.Line(geometry, material);
scene.add(line);

Note: 

• You need to call geometry.computeLineDistances() to make the dash work
• computeLineDistances( ) only works with Geometry (Not work with BufferGeometry)
• The linewidth has no effect in Windows, it is always equals 1

Null safe expression in Thymeleaf

Using '?' after the variable in Thymeleaf expression, that variable will be null safe.

<td th:text="${user.department?.name}"></td>

For the avoid example, even variable department is null, the expression will still be fine.

OpenLayers blurry map with ArcGIS tiles

Check this out:

https://github.com/openlayers/openlayers/issues/6430

Skip testing in Maven

To skip the unit testing in Maven, we need to set the environment variable "maven.test.skip" to true. Or we can use "-DskipTests"

Sample command:

Prompt> mvn package -Dmaven.test.skip=true

OR

Prompt> mvn package -DskipTests

Reference:

https://www.mkyong.com/maven/how-to-skip-maven-unit-test/

Query windows patch via command line

To check if a windows patch (e.g. KB1234567) has been installed, run the following command line:

     C:> wmic qfe | find "1234567"

KVM with NKRO keyboard

Most KVM (e.g. ATEN CS62U) won't compatible with NKRO (N-Key Roll Over) keyboard (e.g. Most mechanical keyboard are with NKRO).

So please pay more attention when purchasing a KVM for NKRO keyboard.

git commands

There are some useful git commands:

Setup a repository:

     git init --bare

Copy an existing repository:

     git clone drive:

Add file to repository:

     git add file
     git commit
     git push

Get updated files from repository:

     git fetch

Merge updated files to my workspace:

     git merge

Web Application Firewall (WAF)

By definition, WAF is going to filter out web request containing SQL injection, cross-site scripting, etc.

Ref: https://www.owasp.org/index.php/Web_Application_Firewall

Smallest font size in Chrome

Since Chrome has a smallest font size setting, you can't use CSS to set font size less than (12px, by default):

   font-size: 6px !important; /* This has no effect ! Sigh .. */


Instead, you may consider to use transform instead:

   transform: scale(0.833); /* 10/12 = 0.833 */


And you may also consider to shift the <div> container to fix the position changed by transform:

   position: relative;
   left: -15px;

Backup and Restore with PostgreSQL

Enter psql
DOS> psql -U user database_name
DOS> psql database_name (if no password defined)

Drop DB
DOS> dropdb database_name
PSQL# drop database database_name

Create DB
DOS> createdb database_name
PSQL# create database database_name

Dump DB
DOS> pg_dump database_name > file_name

Restore from Dump
DOS> psql -U user -d database_name -f file_name