Jan 2, 2023
Install LAMP server
Create new Linode.
Login via ssh
sudo apt update
sudo apt upgrade
sudo reboot
Add new admin user.
adduser sammy
sudo usermod -aG sudo sammy
Install mySQL server
instructions at
https://www.digitalocean.com/community/tutorials/how-to-install-mysql-on-ubuntu-22-04
sudo apt install mysql-server
Make sure mySQL server is running:
sudo systemctl status mysql.service
Prevent error that would occur when running secure install:
sudo mysql
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
This command will show whether the previous command was successful:
SELECT user,plugin,host FROM mysql.user;
Output:
mysql> SELECT user,plugin,host FROM mysql.user;
+------------------+-----------------------+-----------+
| user | plugin | host |
+------------------+-----------------------+-----------+
| debian-sys-maint | caching_sha2_password | localhost |
| mysql.infoschema | caching_sha2_password | localhost |
| mysql.session | caching_sha2_password | localhost |
| mysql.sys | caching_sha2_password | localhost |
| phpmyadmin | caching_sha2_password | localhost |
| root | mysql_native_password | localhost |
| sammy | caching_sha2_password | localhost |
+------------------+-----------------------+-----------+
7 rows in set (0.00 sec)
exit
Now we can run the secure installation script:
sudo mysql_secure_installation
will ask for password, is now 'password'
Output:
Securing the MySQL server deployment.
Enter password for user root:
The 'validate_password' component is installed on the server.
The subsequent steps will run with the existing configuration
of the component.
Using existing password for root.
Estimated strength of the password: 50
Change the password for root ? ((Press y|Y for Yes, any other key for No) : n
... skipping.
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.
Remove anonymous users? (Press y|Y for Yes, any other key for No) : n
... skipping.
Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : n
... skipping.
By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : n
... skipping.
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.
All done!
Add another user
mysql -u root -p
CREATE USER 'sammy'@'localhost' IDENTIFIED BY 'password';
GRANT CREATE, ALTER, DROP, INSERT, UPDATE, INDEX, DELETE, SELECT, REFERENCES, RELOAD on *.* TO
'sammy'@'localhost' WITH GRANT OPTION;
FLUSH PRIVILEGES;
exit
Test new user
mysql -u sammy -p
list databases:
SHOW DATABASES;
Output:
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)
Create new database
CREATE DATABASE db_name;
SHOW DATABASES;
Output:
SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| db_name |
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
The newly created database is listed.
Change the password
mysql -u sammy -p
ALTER USER 'sammy'@'localhost' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;
Install Apache web server
Instructions at
https://www.digitalocean.com/community/tutorials/how-to-install-the-apache-web-server-on-ubuntu-22-04
sudo apt install apache2
Open browser at
http://45.79.28.148/
Apache2 Default Page message comes up - it works.
I am not changing the ufw firewall for now because my deno servers will use port 8000.
Install PHP
Instructions at
https://www.digitalocean.com/community/tutorials/how-to-install-linux-apache-mysql-php-lamp-stack-on-ubuntu-22-04
sudo apt install php libapache2-mod-php php-mysql
Test the installation:
php -v
Install phpmyadmin
Instructions at
https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-phpmyadmin-on-ubuntu-22-04
sudo apt install phpmyadmin php-mbstring php-zip php-gd php-json php-curl
Make sure to select Apache!
Test phpmyadmin
http://45.79.28.148/phpmyadmin
Run deno app on linode server
http://45.79.28.148:8000
deno and mySQL
deno module:
https://deno.land/x/mysql@v2.10.2
Example 1:
https://codeforgeek.com/deno-and-mysql-connection-tutorial/
Setup:
- User sammy has no password
- sammy creates a database named "sammydb"
- sammy creates a table named table1
- deno code is run on the same server as the mysql database
Configuration:
hostname: "127.0.0.1",
username: "sammy",
db: "sammydb",
poolSize: 3, // connection limit
password: "",
const users = await client.query(`select * from table1`);
Output:
~/github/learn/deno/deno_mysql/deno_mysql_01$ deno run --allow-net deno_mysql_01_local.ts
INFO connecting 127.0.0.1:3306
INFO connected to 127.0.0.1:3306
[ { col1: 1, col2: 3, col3: 8, col4: 6 }, { col1: 1, col2: 3, col3: 8, col4: 6 } ]
If I run the code from another location and change the hostname
hostname: "45.79.28.148",
I get
deno run --allow-net deno_mysql_01.ts
INFO connecting 45.79.28.148:3306
error: Uncaught (in promise) ConnectionRefused: Connection refused (os error 111)
More Examples:
https://www.freecodecamp.org/news/how-to-use-mysql-in-deno-oak/
https://github.com/adeelibr/deno-playground/blob/master/guidelines/setting-up-mysql-mac-os-catalina.md
Jan 4, 2023
deno + fresh + mySQL
Task: write a note writing, saving, and viewing app.
Create the empty new deno with Fresh project:
deno run -A -r https://fresh.deno.dev my-project
Jan 7, 2023
Understanding the showcase example Tasks
https://fresh.deno.dev/showcase
The file routes/index.tsx contains a function Home() which returns the HTML code for the client.
Inside the returned data is an element named
<Todo />
which is declared by the statement
import Todo from "../islands/Todo.tsx";
The Todo element contains a function named Todo().
This function starts with
const [tasks, setTasks] = useState<ITask[]>([]);
which uses the Preact functionality for dealing with states.*
The return value is an array containing two variables:
The first variable is a state, and the second is a function that can be called to update the state using
hooks.
The first parameter is the initial value, in this case an empty array.
The array will contain members of the Task type.
The return of the function contains
- a form
- an element of the type Tasks which is declared in the import.
The form contains
- the onSubmit function
- a textbox for entering a new task
- a button to trigger the submit for the form
The Tasks element returns a div tag
within which a function is called that returns an element of type Task.
The Task element returns a div tag
which contains
- a paragraph with the text of the todo which is retrieved from the desc parameter of the props
passed
- a button to remove the task
tasks: ITask[];
removeTask:
* More information on hooks:
https://preactjs.com/tutorial/04-state/
https://www.w3schools.com/react/react_usestate.asp
Jan 9, 2023
What are the parameters and functions that can be called on a UI element?
For example, right-clicking on the word input and choosing opens the file jsx.d.ts
where input is part of an interface named
"interface IntrinsicElements"
input: HTMLAttributes<HTMLInputElement> & { defaultValue?: string };
and right-clicking on textarea takes us to
textarea: HTMLAttributes<HTMLTextAreaElement>;
More information at
https://reactjs.org/docs/forms.html
Jan 14, 2023
Replaced the function crypto.randomUUID() with a function that uses Math.random().
Now it runs on a non-secure server that uses http://
Jan 15, 2023
Try to run the mySQL example - fails with error message:
INFO connecting 127.0.0.1:3306
INFO close connection
error: Uncaught (in promise) Error: Access denied for user 'atmelino'@'localhost' (using password: YES)
throw new Error(error.message);
Now, when I open a terminal and log into mySQL with this user
mysql -u atmelino -p
and run the program again, it works - multiple times.
Reboot the computer.
Is mySQL running?
sudo systemctl status mysql.service
yes:
mysql.service - MySQL Community Server
Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2023-01-15 20:37:16 CST; 1min 57s ago
Process: 899 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
Main PID: 989 (mysqld)
Status: "Server is operational"
Tasks: 39 (limit: 9058)
Memory: 425.7M
CPU: 1.333s
CGroup: /system.slice/mysql.service
└─989 /usr/sbin/mysqld
login to mySQL as different user - still get Access denied error
login to mySQL as the same user as the deno program - deno program works!
Jan 16, 2023
Adding the code for connecting the mySQL database to the deno Frash code
leads to an error in the browser:
wasm.js:214 Uncaught RangeError: WebAssembly.
Compile is disallowed on the main thread, if the buffer size is larger than 4KB.
Use WebAssembly.compile, or compile on a worker thread.
at wasm.js:214:20
Possible solutions
https://github.com/dyedgreen/deno-sqlite/issues/105
Jan 19, 2023
Postgre example 2
https://deno.com/deploy/docs/tutorial-postgres
The place for connection pooling is not under database, it is under settings -> database
The password in the connection string needs to be added without the [] characters.
I can connect to the database from the command line
psql -h db.lwbjwhxdyxafkxjdldmn.supabase.co -p 5432 -d postgres -U postgres
and it will show the todos table that was created with the playground program.
Jan 20, 2023
Postgre example 2 - ctd.
Running the example locally requires either using the environment variable system
https://stackoverflow.com/questions/61873926/where-does-deno-env-got-its-data-from
change code to
import { config } from "https://deno.land/x/dotenv/mod.ts";
const databaseUrl = config().DATABASE_URL;
and setting the environment variable DATABASE_URL to the according value
or simply set the string
const databaseUrl = "postgres://postgres:deno1pass2word3@db.lwbjwhxdyxafkxjdldmn.supabase.co:6543/postgres";
With the server running locally, we can now use the API using cURL:
curl -X GET http://localhost:8000/todos
curl -X POST -d '"Buy cereal"' http://localhost:8000/todos
Run deno app on remote server
ssh into remote server
run the deno app
On local terminal:
curl -X GET http://45.79.28.148:8000/todos
curl -X POST -d '"Buy light bulbs"' http://45.79.28.148:8000/todos
works:
- run curl command in a local terminal
- deno app runs on a remote server
- database runs on supabase
Use local Postgre database
- replace pool.connect() with client.connect()
- replace connection.queryObject with client.queryArray
We can now
- run curl command in a local terminal
- deno app runs on local computer
- database runs on local compter
Jan 21, 2023
Postgre database and deno app on remote server
Install Postgre as described above.
copy the local deno app to remote server and run it
works:
- run curl command in a local terminal
- deno app runs on remote computer
- database runs on remote computer
Jan 22, 2023
Deno Postgres with Deno Fresh
Both the postgre deno app and the deno Fresh todo app use port 8000.
Solution: change the deno Fresh todo app to use port 7000.
in main.ts:
await start(manifest, { port: 7000, plugins: [twindPlugin(twindConfig)] });
Both deno apps can now run in parallel.
HTTP request in deno
https://examples.deno.land/http-requests
Jan 23, 2023
running the two deno apps parallel leads to a problem with CORS:
browser gives error message
Access to fetch at 'http://localhost:8000/todos' from origin 'http://localhost:7000'
has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present
on the requested resource. If an opaque response serves your needs, set the request's
mode to 'no-cors' to fetch the resource with CORS disabled.
https://stackoverflow.com/questions/62301531/deno-oak-disable-cors
create an oak server
https://www.robinwieruch.de/deno-oak-rest-api/
Write the server in oak and disable CORS.
Running the deno Fresh app on port 7000 and the database connection server on port 8000 - works!
