Network Functions¶

In this section, we will cover the following functions in-depth listed below:

uadmin.AllowedHosts
uadmin.AllowedIPs
uadmin.BindIP
uadmin.BlockedIPs
uadmin.CheckRateLimit
uadmin.GetRemoteIP
uadmin.Port
uadmin.RateLimit
uadmin.RateLimitBurst
uadmin.RestrictSessionIP
uadmin.ValidateIP

uadmin.AllowedHosts¶

// Type: string
var AllowedHosts = "0.0.0.0,127.0.0.1,localhost,::1"

AllowedHosts is a comma seprated list of allowed hosts for the server to work. The default value if only for development and production domain should be added before deployment.

uadmin.AllowedIPs¶

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// Type: string
var AllowedIPs = "*"

AllowedIPs is a list of allowed IPs to access uAdmin interface in one of the following formats:

“*” = Allow all
“” = Allow none
“192.168.1.1” = Only allow this IP
“192.168.1.0/24” = Allow all IPs from 192.168.1.1 to 192.168.1.254

You can also create a list of the above formats using comma to separate them.

For example: “192.168.1.1, 192.168.1.2, 192.168.0.0/24”

To assign a value within an application, visit Allowed IPs page for an example.

To assign a value in the code, follow this approach:

Go to the main.go and assign your IP address connected on your PC in the AllowedIPs function.

func main() {
    // NOTE: This code works only if database does not exist yet.
    uadmin.AllowedIPs = "192.168.1.1"

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Assign the Allowed IP value to "192.168.1.1"
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.AllowedIPs")
    setting.ParseFormValue([]string{"192.168.1.1"})
    setting.Save()
}

Run your application and see what happens.

Quiz:

Miscellaneous Functions (3)

uadmin.BindIP¶

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// Type: string
var BindIP = ""

BindIP is the IP the application listens to.

Used in the tutorial:

Go to the main.go. Connect to the server using a loopback IP address (127.x.x.x). Let’s say 127.0.0.2.

func main() {
    // Some codes
    uadmin.BindIP = "127.0.0.2" // <--  place it here
}

If you run your code,

[   OK   ]   Initializing DB: [13/13]
[   OK   ]   Synching System Settings: [51/51]
[   OK   ]   Server Started: http://127.0.0.2:8080
         ___       __          _
  __  __/   | ____/ /___ ___  (_)___
 / / / / /| |/ __  / __  __ \/ / __ \
/ /_/ / ___ / /_/ / / / / / / / / / /
\__,_/_/  |_\__,_/_/ /_/ /_/_/_/ /_/

In the Server Started, it will redirect you to the IP address of 127.0.0.2.

But if you connect to other private IP addresses, it will not work as shown below (User connects to 127.0.0.3).

Quiz:

IP Configuration

uadmin.BlockedIPs¶

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// Type: string
var BlockedIPs = ""

BlockedIPs is a list of blocked IPs from accessing uAdmin interface in one of the following formats:

“*” = Block all
“” = Block none
“192.168.1.1” = Only block this IP
“192.168.1.0/24” = Block all IPs from 192.168.1.1 to 192.168.1.254

You can also create a list of the above formats using comma to separate them.

For example: “192.168.1.1, 192.168.1.2, 192.168.0.0/24”

To assign a value within an application, visit Blocked IPs page for an example.

To assign a value in the code, follow this approach:

Go to the main.go and assign your IP address connected on your PC in the BlockedIPs function.

func main() {
    // NOTE: This code works only if database does not exist yet.
    uadmin.BlockedIPs = "192.168.1.1"

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Assign the Blocked IP value to "192.168.1.1"
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.BlockedIPs")
    setting.ParseFormValue([]string{"192.168.1.1"})
    setting.Save()
}

Run your application and see what happens.

Quiz:

Miscellaneous Functions (3)

uadmin.CheckRateLimit¶

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func CheckRateLimit(r *http.Request) bool

CheckRateLimit checks if the request has remaining quota or not. If it returns false, the IP in the request has exceeded their quota.

Before we proceed to the example, read Tutorial Part 9 - Introduction to API to familiarize how API works in uAdmin.

Create a file named check_rate_limit.go inside the api folder with the following codes below:

package api

import (
    "net/http"
    "strings"

    "github.com/uadmin/uadmin"
)

// CheckRateLimitHandler !
func CheckRateLimitHandler(w http.ResponseWriter, r *http.Request) {
    // r.URL.Path creates a new path called "/check_rate_limit/"
    r.URL.Path = strings.TrimPrefix(r.URL.Path, "/check_rate_limit")
    r.URL.Path = strings.TrimSuffix(r.URL.Path, "/")

    // Call the function to check the status of the rate limit
    checkRateLimit := uadmin.CheckRateLimit(r)

    // Print the result
    uadmin.Trail(uadmin.DEBUG, "Rate Limit: %t", checkRateLimit)
}

Establish a connection in the main.go to the API by using http.HandleFunc. It should be placed after the uadmin.Register and before the StartServer.

func main() {
    // Some codes

    // CheckRateLimitHandler
    http.HandleFunc("/check_rate_limit/", uadmin.Handler(api.CheckRateLimitHandler))
}

api is the folder name while CheckRateLimitHandler is the name of the function inside check_rate_limit.go.

Run your application and go to the check_rate_limit URL path in the address bar using your IP address (e.g. 0.0.0.0:8080/check_rate_limit).

This will not display anything in the webpage but a white screen. Go to your terminal to see the result.

[  DEBUG ]   Rate Limit: true

It means the website is working properly. Now go to admin URL path in the address bar (e.g. 0.0.0.0:8080/admin). From uAdmin dashboard, click on “SETTINGS”.

Change the value of either the Rate Limit or Rate Limit Burst to 0.

../_images/ratelimitvaluehighlighted.png

Result

Slow down. You are going too fast!

Now go to check_rate_limit URL path in the address bar (e.g. 0.0.0.0:8080/check_rate_limit).

This will not display anything in the webpage but a white screen. Go to your terminal to see the result.

[  DEBUG ]   Rate Limit: false

It means the website is crashing. In order to work, either delete the uadmin.db file on your project folder or apply the method shown in uadmin.RateLimit or uadmin.RateLimitBurst where the value is higher than zero.

Quiz:

Rate Limit Functions

uadmin.GetRemoteIP¶

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func GetRemoteIP(r *http.Request) string

GetRemoteIP is a function that returns the IP for a remote user from a request.

uadmin.Port¶

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// Type: int
var Port = 8080

Port is the port used for http or https server.

To assign a value within an application, visit Port page for an example.

To assign a value in the code, follow this approach:

Go to the main.go in your Todo list project and apply 8000 as a port number.

func main() {
    // NOTE: This code works only if database does not exist yet.
    uadmin.Port = 8000

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Assign the Port value to 8000
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.Port")
    setting.ParseFormValue([]string{"8000"})
    setting.Save()
}

If you run your code,

[   OK   ]   Initializing DB: [13/13]
[   OK   ]   Synching System Settings: [51/51]
[   OK   ]   Server Started: http://0.0.0.0:8000
         ___       __          _
  __  __/   | ____/ /___ ___  (_)___
 / / / / /| |/ __  / __  __ \/ / __ \
/ /_/ / ___ / /_/ / / / / / / / / / /
\__,_/_/  |_\__,_/_/ /_/ /_/_/_/ /_/

In the Server Started, it will redirect you to port number 8000.

Quiz:

IP Configuration

uadmin.RateLimit¶

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var RateLimit int64 = 3

RateLimit is the maximum number of requests/second for any unique IP.

To assign a value within an application, visit Rate Limit page for an example.

To assign a value in the code, follow this approach:

Go to the main.go and apply the following codes below:

func main() {
    // NOTE: This code works only if database does not exist yet.
    uadmin.RateLimit = 1

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Assign the Rate Limit value to 1
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.RateLimit")
    setting.ParseFormValue([]string{"1"})
    setting.Save()
}

Run your application. From uAdmin dashboard, hold the Ctrl Key on your keyboard then click any dashboard menu in the form really fast to add in a new tab and see what happens.

The title bar name looks different in the last two tabs. Click any of them to see the result.

The website is crashed as expected. In fact that our rate limit is 1, it might take a long time to bring the website back to normal. To increase the recovery rate, adjust the rate limit to a higher value (e.g. 100).

// Assign the Rate Limit value to 100
setting := uadmin.Setting{}
uadmin.Get(&setting, "code = ?", "uAdmin.RateLimit")
setting.ParseFormValue([]string{"100"})
setting.Save()

Run your application again and do the same process as shown above. Afterwards, click any button in the form and you will see that the website is back to normal much faster.

Quiz:

Rate Limit Functions

uadmin.RateLimitBurst¶

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var RateLimitBurst int64 = 3

RateLimitBurst is the maximum number of requests for an idle user.

To assign a value within an application, visit Rate Limit Burst page for an example.

To assign a value in the code, follow this approach:

Go to the main.go and apply the following codes below:

func main() {
    // NOTE: This code works only if database does not exist yet.
    uadmin.RateLimitBurst = 3

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Assign the Rate Limit Burst value to 3
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.RateLimitBurst")
    setting.ParseFormValue([]string{"3"})
    setting.Save()
}

Run your application. From uAdmin dashboard, hold the Ctrl Key on your keyboard then click any dashboard menu in the form really fast to add in a new tab and see what happens.

The title bar name looks different in the last two tabs. Click any of them to see the result.

The website is crashed because our request exceeds the limit that we have assigned.

Quiz:

Rate Limit Functions

uadmin.RestrictSessionIP¶

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// Type: bool
var RestrictSessionIP = false

RestrictSessionIP is to block access of a user if their IP changes from their original IP during login.

To assign a value within an application, visit Restrict Session IP page for an example.

To assign a value in the code, follow this approach:

Example:

package main

import (
    "github.com/uadmin/uadmin"
)

func main() {
    // NOTE: This code works only if database does not exist yet.
    // Block access of a user
    uadmin.RestrictSessionIP = true

    // Allow access of a user
    uadmin.RestrictSessionIP = false

    // ----- IF YOU RUN YOUR APPLICATION AGAIN, DO THIS BELOW -----

    // Block access of a user
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.RestrictSessionIP")
    setting.ParseFormValue([]string{"true"})
    setting.Save()

    // Allow access of a user
    setting := uadmin.Setting{}
    uadmin.Get(&setting, "code = ?", "uAdmin.RestrictSessionIP")
    setting.ParseFormValue([]string{"false"})
    setting.Save()
}

Quiz:

Miscellaneous Functions (3)

uadmin.ValidateIP¶

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func ValidateIP(r *http.Request, allow string, block string) bool

ValidateIP is a function to check if the IP in the request is allowed in the allowed based on allowed and block strings.

Before we proceed to the example, read Tutorial Part 9 - Introduction to API to familiarize how API works in uAdmin.

Create a file named validation_ip.go inside the api folder with the following codes below:

package api

import (
    "net/http"
    "strings"

    "github.com/uadmin/uadmin"
)

// ValidateAPIHandler !
func ValidateAPIHandler(w http.ResponseWriter, r *http.Request) {
    // r.URL.Path creates a new path called "/validate_ip"
    r.URL.Path = strings.TrimPrefix(r.URL.Path, "/validate_ip")
    r.URL.Path = strings.TrimSuffix(r.URL.Path, "/")

    // Allowed IP - 192.168.1.1 (Your IP address)
    // Blocked IP - 192.168.1.2 (IP that was binded from other PC)
    validateIP := uadmin.ValidateIP(r, "192.168.1.1", "192.168.1.2")

    // Print the result
    uadmin.Trail(uadmin.DEBUG, "Validate IP: %t", validateIP)
}

Establish a connection in the main.go to the API by using http.HandleFunc. It should be placed after the uadmin.Register and before the StartServer.

func main() {
    // Some codes

    // ValidateAPIHandler
    http.HandleFunc("/validate_ip/", uadmin.Handler(api.ValidateAPIHandler))
}

api is the folder name while ValidateAPIHandler is the name of the function inside validation_ip.go.

Run your application and go to the validate_ip URL path in the address bar using your IP address (e.g. 192.168.1.1:8080/validate_ip).

This will not display anything in the webpage but a white screen. Go to your terminal to see the result.

[  DEBUG ]   Validate IP: true

Now go to the validate_ip URL path in the address bar using the binded IP (e.g. 192.168.1.2:8080/validate_ip). Make sure that the IP from other PC is binded to your computer. Otherwise, it will not work.

This will not display anything in the webpage but a white screen. Go to your terminal to see the result.

[  DEBUG ]   Validate IP: false

Quiz:

Miscellaneous Functions (3)

Network Functions¶

uadmin.AllowedHosts¶

uadmin.AllowedIPs¶

uadmin.BindIP¶

uadmin.BlockedIPs¶

uadmin.CheckRateLimit¶

uadmin.GetRemoteIP¶

uadmin.Port¶

uadmin.RateLimit¶

uadmin.RateLimitBurst¶

uadmin.RestrictSessionIP¶

uadmin.ValidateIP¶

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