Connect to a Private network via proxy server from macOS

Muhammad Hewedy — Thu, 22 Apr 2021 17:44:53 +0000

In this post, we will see how to connect from mac to another machine (as a forwarding proxy) then to the internet (or to a private network 😉).

The steps will focus to macos client, but it can be any other OS.

First, You need to install squid proxy on your Windows/Linux box (the jump box). there are many ways to do so, in my case I used a docker image for squid proxy.

docker run -d -p 3128:3128 --restart unless-stopped cosmicq/docker-squid

Now, go to macOS, and you need to change the proxy settings in two places, the System Preferences > Network and in the shell.

System Preferences

For System Preferences > Network, Click Advanced, then go to the proxy tab and in the http and https sections, enter the ip/port of the proxy:

Note, you can use commands to set the proxy instead of using GUI, as follows:

networksetup -setwebproxy wi-fi 192.168.100.39 3128
networksetup -setwebproxystate wi-fi on
networksetup -setsecurewebproxystate wi-fi on

This will make it easy to enable/disable the proxy setting on a user basis.

The shell

The last step is to set the http_proxy and https_proxy in your shell.

You can append the following at the end of your ~/.zshrc file:

export http_proxy="192.168.100.39:3128"
export https_proxy=$http_proxy

Happy proxying!

Update

The squid proxy works well for HTTP/HTTPS traffic. however, some traffic is TCP traffic. There are different solutions to this problem, but I fixed it by using a native port-forward solution in windows using the command netsh.

In my case, I needed to access a DB server accessible from windows machine by 192.168.100.100/1433, so I run the following command in windows cmd (as administrator)

netsh interface portproxy add v4tov4 listenport=14330 connectport=1433 connectaddress=192.168.100.100

which will open port 14330 on the windows machine and forward traffic to the DB server at 192.168.100.100 on port 1433.

Now I can connect to the DB server from mac on the windows IP address (in my case 192.168.100.39) on port 14330.

To delete the port-forwarding:

netsh interface portproxy delete v4tov4 listenport=14330

To list port-forwarding:

netsh interface portproxy show v4tov4

References:
https://github.com/CosmicQ/docker-squid
https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc731068(v=ws.10)?redirectedfrom=MSDN

Using MongoDB query syntax to query Relational Database in Java

Muhammad Hewedy — Fri, 26 Mar 2021 18:53:09 +0000

Spring Data JPA provides a lot of features on top of JPA. Such as Query methods, Query by examples, and a lot more.

It also integrates with JPA Specifications, QueryDSL, Jooq, and other fantastic libraries.

However there’s a specific use-case that exists in most applications which is the need to make the user search by multiple criteria for an entity and its related associations. This is where Spring Data JPA Mongodb Expressions excels.

Spring Data JPA MongoDB Expressions allows you to use MongoDB query syntax to send the queries as JSON string typically from the frontend app to a Rest API and then to the Repository layer.

Here’s an example query that users can send from the frontend:

{
  "lastName": "ibrahim",
  "$and": [
    {
      "birthDate": {"$gt": "1981-01-01"}
    },
    {
      "birthDate": {"$lte": "1985-10-10"}
    }
  ]
}

that will be translated to:

... where last_name=? and birth_date>? and birth_date<=?

As you see, it uses the same notation of the initiative and simple-to-use MongoDB query language with features such as ANDing, ORing, and joining entities.

So How to start?

You can follow the README file on the project page at Github, it contains a lot of details.