Monday, February 24, 2025

Make RPM package on Fedora and RedHat

To create a Golf  installation package for Fedora or RedHat (or similar based on those, like Rocky), first get Golf source code. To do that, install git first:

sudo dnf install git

Then get Golf source code:

git clone https://github.com/golf-lang/golf.git
cd golf

For Redhat/Rocky/etc. install EPEL:

sudo dnf install epel-release

Next, install rpm-build package:

sudo dnf install rpm-build

On Fedora,

Sunday, February 23, 2025

DEB package on Ubuntu and Debian

If you'd like to create a Golf  installation package for Ubuntu or Debian (or similar based on those), first get Golf source code. To do that, install git first:

sudo apt update
sudo apt install git

Then get Golf source code:

git clone https://github.com/golf-lang/golf.git
cd golf

Before you can create a package, you must first install Debian tools:

sudo apt update
sudo apt -y install devscripts equivs build-essential lintian

Next,

Golf 261 released

  • Added Fedora spec file for building RPM packages, and for upcoming COPR builds on Fedora infrastructure cloud service.
  • Fixed a compilation issue with RedHat regarding _GNU_SOURCE flag.
  • Refactor Golf memory code for about 10% better performance in memory-access intensive applications.  

Friday, February 21, 2025

34000 requests per second on a modest laptop

Here's a video showing how to create and start an application server, and how to connect to it and make requests from a C client (or from any language that supports C API extension):


Create new directory for the Golf server and also for C API client:
mkdir -p srv-example
cd srv-example
mkdir -p client

Create file "srv.golf" and copy this:
 begin-handler /srv public
     silent-header
     @Hello world!
 end-handler

Create Golf application server:
gg -k hello

Build Golf application server (exclude client directory as it contains C API client):
gg -q --exclude-dir=client

Start the application server (a single-process server in this case):
mgrg -w 1 hello

Next, go to C API client directory:
cd client

Then create C file "cli.c" and copy this:
 #include "gcli.h"

 int golf_client (gg_cli *req, char *connection, char *method, char *app_path, char *request, char *url_params);

 int golf_client (gg_cli *req, char *connection, char *method, char *app_path, char *request, char *url_params)
 {
     memset ((char*)req, 0, sizeof(gg_cli));
     req->server = connection;
     req->req_method = method;
     req->app_path = app_path;
     req->req = request;
     req->url_params = url_params;
     return gg_cli_request (req);
 }

 void main ()
 {
     int i;
     for (i = 0; i < 100000; i++)
     {
         gg_cli req;
         int res = golf_client (&req, "/var/lib/gg/hello/sock/sock", "GET", "/hello", "/srv", "/");
         if (res != GG_OKAY) printf("Request failed [%d] [%s]\n", res, req.errm);
         else printf("%s", gg_cli_data(&req));
         gg_cli_delete(&req);
     }
 }

Compile the client:
gcc -o cli cli.c $(gg -i) -O3

Run it:
./cli

The result is "Hello world!" 1,000,000 times from each request invocation.

Wednesday, February 19, 2025

Golf 253 released

  • Fixed a memory leak that happens in rare situations with internal memory reallocation.
  • Improved performance with request memory management.
  • Improved performance with queries (across all databases, PostgreSQL, MariaDB, SQLite) with reduced number of memory copies and memory allocations.

Sunday, February 16, 2025

Golf 247 released

  • Fixed bug with lists, where if process-scoped, data retrieved with read-list statement may in some rare cases be inaccurate.
  • About 2% speed-up in request execution, due to refactoring of memory cleanup at the end of each request.

Thursday, February 13, 2025

Golf 244 released

  • This release brings much faster memory for large-data servers, for instance servers that hold millions of rows organized in trees, hashes etc. The change is about separating ordinary memory used by a request (such as variables) from the process-scoped memory (which can hold lots of data). The performance improvement is mostly in a high-load environments, for instance when there are tens of thousands of requests per second inserting, deleting or querying data.  

Wednesday, February 12, 2025

Use C language API to talk to Golf Server

Golf application server can be accessed via C API. Most programming languages allow for C linkage, so this makes it easy to talk to Golf server from anywhere. The Client-API is very simple with just a few functions and a single data type. It's also MT-safe (i.e. safe for multi-threaded applications).

In this example, a Golf server will use a tree object to store key/value pairs, which can be added, queried and deleted for as long as the server is running (i.e. it's an in-memory database, or a cache server). Client will insert the key/value pairs, query and delete them.
Create a server and start it
To get started, create a directory for this example and position in it:
mkdir -p c-api
cd c-api

Save this into a file "srv.golf":
 begin-handler /srv public
     silent-header
     do-once
         new-tree ind process-scope
     end-do-once
     get-param op
     get-param key
     get-param data
     if-true op equal "add"
         write-tree ind key (key) value data status st
         if-true st equal GG_ERR_EXIST
             @Key exists [<<p-out key>>]
         else-if
             @Added [<<p-out key>>]
         end-if
     else-if op equal "delete"
         delete-tree ind key (key) value val status st
         if-true st equal GG_ERR_EXIST
             @Not found [<<p-out key>>]
         else-if
             @Deleted, old value was [<<p-out val>>]
         end-if
     else-if op equal "query"
         read-tree ind equal (key) value val status st
         if-true st equal GG_ERR_EXIST
             @Not found, queried [<<p-out key>>]
         else-if
             @Value [<<p-out val>>]
         end-if
     end-if
 end-handler

Create "index" application ("-k"):

Tuesday, February 11, 2025

Golf 241 released

  • This release improves memory handling, which is now faster. Also, several issues with process-scoped memory, such as leaking in some cases, has been resolved. 
  • delete-string will now always delete ordinary (non process-scoped) memory if not referenced prior to deletion, otherwise memory is always released at the end of request. This strikes a good balance between the ability to delete memory while request is executing (if needed), and at the same time, have an automatic memory de-allocator and safety mechanism that's high-performance because it's very lightweight. 

Saturday, February 8, 2025

Golf 231 released

  • Fixed memory issue with long running server processes when using process-scoped memory with a tree object. The problem would in some situations utilize more memory than needed. This fixes the issue and improves performance.  
  • Option "--optimize-memory" has been removed from gg utility due to adding an overhead for the benefit that's generally proven negligible.

Tuesday, February 4, 2025

Golf package page on AUR for Arch Linux

Golf's AUR page is https://aur.archlinux.org/packages/golf

You can build a pacman package from it, and install Golf from that package (on this or other machines):

git clone https://aur.archlinux.org/golf.git
cd golf
makepkg -sirc

Sunday, February 2, 2025

Ubuntu apt package available for Golf

You can install Golf from precompiled binaries provided by Launchpad which is Ubuntu service that builds Golf directly from its github source code repo.  

You would add Golf repo:

sudo add-apt-repository ppa:golf-lang/golf
sudo apt update

And then install Golf with:

sudo apt install golf

You can then manage the package using standard Ubuntu apt tools.

Golf 210 released

  • Added new "error-line" and "error-char" clauses in JSON parsing (json-doc statement) to produce the line number and the character within the line where error in parsing was detected.
  • Fixed a build bug with missing 'stub_xml.o' file. This file is a part of upcoming XML parsing support and plays no role currently, but it prevented the build from being completed.
  • Fixed issue with maximum length of source code line, which should be approx 8K.
  • Added debian apt package build support (debian/control etc.) 

Thursday, January 30, 2025

How to send email with Golf

This example shows how to send email with Golf. The web service you'll create here is very simple and it will display an HTML form to collect info needed to send email, such as "From" and "To" (the sender and the recipient emails), the Subject and of course the Message itself. Once user clicks Submit, email is sent.

Create directory for your application:
mkdir -p mail
cd mail

Create "mail-sender" application:
gg -k mail-sender

Copy the following code to file "mail.golf":
 begin-handler /mail public
     // Get URL parameter
     get-param action

     if-true action equal "show_form"
         // Display HTML form
         @<h2>Enter email and click Send to send it</h2>
         @Note: 'From' field must be the email address from the domain of your server.<br/><br/>
         @<form action="<<p-path "/mail">>" method="POST">
         @    <input type="hidden" name="action" value="submit_form">
         @    <label for="from_mail">From:</label><br>
         @    <input type="text" name="from_mail" value=""><br>
         @    <label for="to_mail">To:</label><br>
         @    <input type="text" name="to_mail" value=""><br><br>
         @    <label for="subject_mail">Subject:</label><br>
         @    <input type="text" name="subject_mail" value=""><br><br>
         @    <label for="message">Message:</label><br>
         @    <textarea name="message" rows="3" columns="50"></textarea>
         @    <br/><br/>
         @    <input type="submit" value="Send">
         @</form>
     else-if action equal "submit_form"
         // Get data from HTML form
         get-param from_mail
         get-param to_mail
         get-param message
         get-param subject_mail
         // Construct email message
         write-string msg
             @From: <<p-out from_mail>>
             @To: <<p-out to_mail>>
             @Subject: <<p-out subject_mail>>
             @
             <<p-out message>>
         end-write-string
         // Send email
         exec-program "/usr/sbin/sendmail" args "-i", "-t" input msg status st
         // Check status of email sending
         if-true st not-equal GG_OKAY
             @Could not send email!
         else-if
             @Email sent!
         end-if
         @<hr/>
     else-if
         @Unrecognized action!<hr/>
     end-if
 end-handler

The example uses

Tuesday, January 28, 2025

Fast JSON parser with little coding

Golf's JSON parser produces an array of name/value pairs. A name is a path to value, for instance "country"."state"."name", and the value is simply the data associated with it, for instance "Idaho". You can control if the name contains array indexes or not, for instance if there are multiple States in the document, you might have names like "country"."state"[0]."name" with [..] designating an array element.

You can iterate through this array and get names of JSON elements, examine if they are of interest to you, and if so, get the values. This typical scenario is how Golf's parser is built, since it uses a "lazy" approach, where values are not allocated until needed, speeding up parsing. That is the case in this example. The JSON document below is examined and only the names of the cities are extracted.

You can also store JSON elements into trees or hashes for future fast retrieval, or store them into a database, etc.

To get started, create a directory for this example and position in it:
mkdir -p json
cd json

Save this JSON into a file "countries.json" - we will get the names of the cities from it:
{ "country": [
    { 
        "name": "USA",
        "state": [
            { 
                "name": "Arizona",
                "city": [
                    {
                        "name" : "Phoenix",
                        "population": 5000000
            	    } ,
                    {
                        "name" : "Tuscon",
                        "population": 1000000
            	    } 

                ]
            } ,
            { 
                "name": "California",
                "city": [
                    {
                        "name" : "Los Angeles",
                        "population": 19000000
            	    },
                    {
                        "name" : "Irvine"
            	    }
                ]
            } 
        ] 
    } ,
    { 
        "name": "Mexico",
        "state": [
            { 
                "name": "Veracruz",
                "city": [
                    {
                        "name" : "Xalapa-Enríquez",
                        "population": 8000000
            	    },
                    {
                        "name" : "C\u00F3rdoba",
                        "population": 220000
            	    }
                ]
            } ,
            { 
                "name": "Sinaloa",
                "city": [
                    {
                        "name" : "Culiac\u00E1n Rosales",
                        "population": 3000000
            	    }
                ]
            } 
        ] 
    }
    ]
}

What follows is the code to parse JSON. We open a JSON file, process the document, check for errors, and then read elements one by one. We look for a key "country"."state"."city"."name" because those contains city names. Note use "no-enum" clause in json-doc (which is the Golf's JSON parser), so that element designations aren't showing (meaning we don't have [0], [1] etc. for arrays).

Save this code to "parse-json.golf":
 begin-handler /parse-json public
     // Read the JSON file
     read-file "countries.json" to countries status st
     if-true st lesser-equal 0
         @Cannot read file or file empty
         exit-handler -1
     end-if

     // Parse JSON
     json-doc countries no-enum status st error-text et error-position ep to json

     // Check for errors in JSON document
     if-true st not-equal GG_OKAY
         @Error [<<p-out et>>] at [<<p-num ep>>]
         exit-handler -2
     end-if

     // This is the JSON element we're looking for
     set-string city_name unquoted ="country"."state"."city"."name"

     // Read elements one by one - note you can then store them in a tree or hash for future fast searches
     start-loop
         // Read just a key
         read-json json key k type t
         // Exit if end of document
         if-true t equal GG_JSON_TYPE_NONE
             break-loop
         end-if
         // If matches key we're looking for, get the value, and output it
         if-true city_name equal k
             read-json json value v
             @Value [<<p-out v>>]
             @--------
         end-if
         // Move on to the next JSON element
         read-json json next
     end-loop

     // Optionally delete JSON object, or it will be automatically deleted
     json-doc delete json
 end-handler

Monday, January 27, 2025

Golf 191 released

  • Fixed bugs in compilation when process-scoped types are not recognized in some cases.
  • Fixed bug in JSON processing that could see in rare cases wrong data produced by parsing. 

Sunday, January 26, 2025

Golf 184 released

  • New "array" type has been added. This is a string array with a number key, ranging from 0 to the array's maximum size. Note that Golf array is flexible: you do not need to specify the array size, rather only it maximum possible size. The actual memory allocated is nominal and will vary based on the data you store in the array. Arrays can also be purged to reduce their size back to the nominal. Statements included are new-array, read-array, write-array and purge-array.
  • Renamed index type to reflect its structure, and now it's "tree". So the statements like new-index, read-index etc. are now new-tree, read-tree etc.
  • Renamed set type to reflect its structure, and now it's "hash". So the statements like new-set, read-set etc. are now new-hash, read-hash etc.

Saturday, January 18, 2025

Golf 171 released

  • "Array" statements are now "set", so for example new-array is now new-set. This change is made to align the names of data structures better with their qualities and to make room for a new "array" structure that will be a direct-memory access structure. Please rename these statements in your code to be compatible with this and future versions.
  • The limit for a number of subdirectories in file storage is now 64000, instead of previous 40000, significantly increasing the number of files that can be stored (theoretically by 240,000,000,000).

Tuesday, January 14, 2025

Golf 155 released

  • Gliimly has been renamed to Golf. New web site is https://golf-lang.com and blog is at https://golf-lang.blogspot.com/
  • Note in order to migrate to Golf you need to:
    1. Uninstall Gliimly (using "sudo make uninstall" from its source code directory).
    2. Install Golf (see https://golf-lang.github.io/install.html)
    3. Rename all your source files to have .golf extension
    4. Rebuild your project (gg -q)
  • File type for source files has changed from .gliimly to .golf
  • Fixed longstanding issue with (sometimes) bad diagnostic output for erroneous source (meaning non-correct error reporting).
  • Added "no-enum" clause in json-doc statement to produce keys for JSON values that do not include array enumeration.

Friday, January 3, 2025

What is application server?

Every Golf application is built as both an application server and a command-line program. You can use both, depending on what's the nature of your application. Some programs are meant to be used in scripts, or executed directly from command line. Others need to stay in memory and execute user requests as servers. The nice thing is that they both work the same, meaning you can run from command line anything that an application server does, and vice versa. This is also handy for testing; it makes writing tests for an application server much easier because you can run such tests in a plain bash script.

What is an application server? It is a set of background resident processes. Each such process can be contacted via socket with a request, and it will provide a reply. An application server often sits behind a web server which accepts user requests, passes them to the application server, receives its reply and the passes this reply back to the user. This is a "reverse proxy" configuration. Note that this configuration, though typical, isn't a hard rule; end users can talk to an application server directly in some cases, such as on a secure local network.

Thursday, December 26, 2024

Encryption: ciphers, digests, salt, IV




What is encryption
Encryption is a method of turning data into an unusable form that can be made useful only by means of decryption. The purpose is to make data available solely to those who can decrypt it (i.e. make it usable). Typically, data needs to be encrypted to make sure it cannot be obtained in case of unauthorized access. It is the last line of defense after an attacker has managed to break through authorization systems and access control.

This doesn't mean all data needs to be encrypted, because often times authorization and access systems may be enough, and in addition, there is a performance penalty for encrypting and decrypting data. If and when the data gets encrypted is a matter of application planning and risk assessment, and sometimes it is also a regulatory requirement, such as with HIPAA or GDPR.

Data can be encrypted at-rest, such as on disk, or in transit, such as between two parties communicating over the Internet.

Here you will learn how to encrypt and decrypt data using a password, also known as symmetrical encryption. This password must be known to both parties exchanging information.
Cipher, digest, salt, iterations, IV
To properly and securely use encryption, there are a few notions that need to be explained.

A cipher is the algorithm used for encryption. For example, AES256 is a cipher. The idea of a cipher is what most people will think of when it comes to encryption.

A digest is basically a hash function that is used to scramble and lengthen the password (i.e. the encryption key) before it's used by the cipher. Why is this done? For one, it creates a well randomized, uniform-length hash of a key that works better for encryption. It's also very suitable for "salting", which is the next one to talk about.

The "salt" is a method of defeating so-called "rainbow" tables. An attacker knows that two hashed values will still look exactly the same if the originals were. However, if you add the salt value to hashing, then they won't. It's called "salt" because it's sort of mixed with the key to produce something different. Now, a rainbow table will attempt to match known hashed values with precomputed data in an effort to guess a password. Usually, salt is randomly generated for each key and stored with it. In order to match known hashes, the attacker would have to precompute rainbow tables for great many random values, which is generally not feasible.

You will often hear about "iterations" in encryption. An iteration is a single cycle in which a key and salt are mixed in such a way to make guessing the key harder. This is done many times so to make it computationally difficult for an attacker to reverse-guess the key, hence "iterations" (plural). Typically, a minimum required number of iterations is 1000, but it can be different than that. If you start with a really strong password, generally you need less.

IV (or "Initialization Vector") is typically a random value that's used for encryption of each message. Now, salt is used for producing a key based on a password. And IV is used when you already have a key and now are encrypting messages. The purpose of IV is to make the same messages appear differently when encrypted. Sometimes, IV also has a sequential component, so it's made of a random string plus a sequence that constantly increases. This makes "replay" attacks difficult, which is where attacker doesn't need to decrypt a message; but rather an encrypted message was "sniffed" (i.e. intercepted between the sender and receiver) and then replayed, hoping to repeat the action already performed. Though in reality, most high-level protocols already have a sequence in place, where each message has, as a part of it, an increasing packet number, so in most cases IV doesn't need it.
Prerequisites
This example uses Golf framework. Install it first.
Encryption example
To run the examples here, create an application "enc" in a directory of its own (see mgrg for more on Golf's program manager):
mkdir enc_example
cd enc_example
gg -k enc

To encrypt data use encrypt-data statement. The simplest form is to encrypt a null-terminated string. Create a file "encrypt.golf" and copy this:
 begin-handler /encrypt public
     set-string str = "This contains a secret code, which is Open Sesame!"
     // Encrypt
     encrypt-data str to enc_str password "my_password"
     p-out enc_str
     @
     // Decrypt
     decrypt-data enc_str password "my_password" to dec_str
     p-out dec_str
     @
 end-handler

You can see the basic usage of encrypt-data and decrypt-data. You supply data (original or encrypted), the password, and off you go. The data is encrypted and then decrypted, yielding the original.

Wednesday, December 25, 2024

Golf 136 released

  • Any number expression can now use string subscription as a number, for instance:
    set-string str='hello'
    set-number num = 10+str[0]

    A character is treated as an unsigned number ranging from 0-255 (i.e. unsigned byte).

Tuesday, December 24, 2024

Golf 132 released

  • Individual bytes of a string (binary or text) can now be set using set-string by specifying the byte with a number expression within []. Since Golf is a memory-safe language, setting a byte this way is subject to a range check. For instance:
    set-string str[10] = 'a'
  • An individual byte of a string (binary or text) can now be obtained (as a number) with set-number using a number expression within []. Since Golf is a memory-safe language, getting a byte this way is subject to a range check. For instance:
    set-number byte = str[10]
Note that Golf is a very high level language, and it generally does not start with low-level constructs, such as setting and retrieving bytes from memory; rather its statements perform tasks that take typically many lines of code in other languages. So it makes sense an addition like this would be a "side-note" undertaken later in the language; it's not the focus of it. Still, Golf is also a high performance language and so the above two new capabilities are implemented with that in mind, with the minimum of overhead.  

Sunday, December 15, 2024

Distributed computing made easy




What is distributed computing
Distributed computing is two or more servers communicating for a common purpose. Typically, some tasks are divvied up between a number of computers, and they all work together to accomplish it. Note that "separate servers" may mean physically separate computers. It may also mean virtual servers such as Virtual Private Servers (VPS) or containers, that may share the same physical hardware, though they appear as separate computers on the network.

There are many reasons why you might need this kind of setup. It may be that resources needed to complete the task aren't all on a single computer. For instance, your application may rely on multiple databases, each residing on a different computer. Or, you may need to distribute requests to your application because a single computer isn't enough to handle them all at the same time. In other cases, you are using remote services (like a REST API-based for instance), and those by nature reside somewhere else.

In any case, the computers comprising your distributed system may be on a local network, or they may be worldwide, or some combination of those. The throughput (how many bytes per second can be exchanged via network) and latency (how long it takes for a packet to travel via network) will obviously vary: for a local network you'd have a higher throughput and lower latency, and for Internet servers it will be the opposite. Plan accordingly based on the quality of service you'd expect.
How servers communicate
Depending on your network(s) setup, different kinds of communication are called for. If two servers reside on a local network, then they would typically used the fastest possible means of communication. A local network typically means a secure network, because nobody else has access to it but you. So you would not need TSL/SSL or any other kind of secure protocol as that would just slow things down.

If two servers are on the Internet though, then you must use a secure protocol (like TSL/SSL or some other) because your communication may be spied on, or worse, affected by man-in-the-middle attacks.
Local network distributed computing
Most of the time, your distributed system would be on a local network. Such network may be separate and private in a physical sense, or (more commonly) in a virtual sense, where some kind of a Private Cloud Network is established for you by the Cloud provider. It's likely that separation is enforced by specialized hardware (such as routers and firewalls) and secure protocols that keep networks belonging to different customers separate. This way, a "local" network can be established even if computers on it are a world apart, though typically they reside as a part of a larger local network.

Either way, as far as your application is concerned, you are looking at a local network. Thus, the example here will be for such a case, as it's most likely what you'll have. A local network means different parts of your application residing on different servers will use some efficient protocol based on TCP/IP. One such protocol is FastCGI, a high-performance binary protocol for communication between servers, clients, and in general programs of all kinds, and that's the one used by Golf. So in principle, the setup will look like this (there'll be more details later):


Next, in theory you should have two servers, however in this example both servers will be on the same localhost (i.e. "127.0.0.1"). This is just for simplicity; the code is exactly the same if you have two different servers on a local network - simply use another IP (such as "192.168.0.15" for instance) for your "remote" server instead of local "127.0.0.1". The two servers do not even necessarily need to be physically two different computers. You can start a Virtual Machine (VM) on your computer and host another virtual computer there. Popular free software like VirtualBox or KVM Hypervisor can help you do that.

In any case, in this example you will start two simple application servers; they will communicate with one another. The first one will be called "local" and the other one "remote" server. The local application server will make a request to the remote one.
Local server
On a local server, create a new directory for your local application server source code:
mkdir ~/local_server
cd ~/local_server

and then create a new file "status.golf" with the following:
 begin-handler /status public
     silent-header
     get-param server
     get-param days

     pf-out "/server/remote-status/days=%s", days to payload
     pf-out "%s:3800", server to srv_location

     new-remote srv location srv_location \
         method "GET" url-path payload \
         timeout 30

     call-remote srv
     read-remote srv data dt
     @Output is: [<<p-out dt>>]
 end-handler

The code here is very simple. new-remote will create a new connection to a remote server

Thursday, December 12, 2024

How is memory organized in Golf

Golf is a high-performance memory-safe language. A string variable is the actual pointer to a string (whether it's a text or binary). This eliminates at least one extra memory read, making string access as fast as in C. Bytes before the string constitute the ID to a memory table entry, with additional info used by memory-safety mechanisms:
  • Length (in bytes) of the string,
  • "Ref count" (Reference count), stating how many Golf variables point to string,
  • Status is used to describe string, such as whether it's scope is process-wide, if it's a string literal etc,
  • "Next free" points to the next available string block (if this one was freed too),
  • "Data ptr" points back to the string, which is used to speed up access.
Memory is always null-terminated, regardless of whether it's text or binary. Here's what that looks like in a picture:


Each memory block (ID+string+trailing null) is a memory allocated by standard C'd memory allocation, while memory table is a continuous block that's frequently cached to produce fast access to string's properties.

Sunday, December 8, 2024

Web file manager in less than 100 lines of code

Uploading and download files in web browser is a common task in virtually any web application or service. This article shows how to do this with very little coding - in less than 100 lines of code. The database used is PostgreSQL, and the web server is Nginx.

You will use Golf as an application server and the programming language. It will run behind the web server for performance and security, as well as to enable richer web functionality. This way end-user cannot talk to your application server directly because all such requests go through the web server, while your back-end application can talk directly to your application server for better performance.

Assuming your currently logged-on Linux user will own the application, create a source code directory and also create Golf application named "file-manager":
mkdir filemgr
cd filemgr
gg -k file-manager

Next, create PostgreSQL database named "db_file_manager", owned by currently logged-on user (i.e. passwordless setup):
echo "create user $(whoami);
create database db_file_manager with owner=$(whoami);
grant all on database db_file_manager to $(whoami);
\q"  | sudo -u postgres psql

Create database configuration file used by Golf that describes the database (it's a file "db"):
echo "user=$(whoami) dbname=db_file_manager" > db

Create SQL table that will hold files currently stored on the server:
echo "create table if not exists files (fileName varchar(100), localPath varchar(300), extension varchar(10), description varchar(200), fileSize int, fileID bigserial primary key);" | psql -d db_file_manager

Finally, create source Golf files. First create "start.golf" file and copy and paste:
 begin-handler /start public
    @<h2>File Manager</h2>
    @To manage the uploaded files, <a href="<<p-path "/list">>">click here.</a><br/>
    @<br/>
    @<form action="<<p-path "/upload">>" method="POST" enctype="multipart/form-data">
    @    <label for="file_description">File description:</label><br>
    @    <textarea name="filedesc" rows="3" columns="50"></textarea><br/>
    @    <br/>
    @    <label for="filename">File:</label>
    @    <input type="file" name="file" value=""><br><br>
    @    <input type="submit" value="Submit">
    @</form>
 end-handler

Create "list.golf" file and copy and paste: