## **Reverse GeoCoding:**

The process of converting latitude and longitude into human readable address is called **Reverse GeoCoding**. 

If you are developing an iOS app in which app allows its user to select the location on map. Then surely you will need to convert the selected latitude and longitude into human readable address by using reverse geocoding, in order to show what address does user has selected. The code for reverse geocoding is pretty straight forward.

&nbsp;

<iframe 
 width="100%"
 height="300" 
 src="data:text/html;charset=utf-8,
 <head><base target='_blank' /></head>
 <body><script src='https://gist.github.com/mzeeshanid/9237b89dd655320ae5215cdc9a8ce11f.js'></script>
 </body>">

&nbsp;

In case if you want to use Google's `GMSGeocoder` then most probably you will run into a situation where you want to entertain the last request only. Didn't understand what I mean? Lets consider the following scenario:

- Your app allows its user to drag the map view in order to change the camera focus. 
- This process can't be blocking for better user experience. 
- User drag to change the camera focus.
- When focus did change your app send the reverse geocoding request.
- Before the request could complete, user change the camera focus again.
- Your app send the new reverse geocoding request.

As the requests are asynchronous, this means there is no guarantee which request will be completed first. So, in this particular case you need to cancel the outstanding reverse geocoding requests before making new requests. But guess what? there is no cancel method for `GMSGeocoder`. 

&nbsp;

![{"alt" : "Frustrated","width": 600,"height": 450,"thumb": "https://dzm9gzl83npws.cloudfront.net/thumbnail_adrian_swancar_7_Ssnka8_Oq_LM_unsplash_68978af5a6.jpg"}](https://dzm9gzl83npws.cloudfront.net/large_adrian_swancar_7_Ssnka8_Oq_LM_unsplash_68978af5a6.jpg)

&nbsp;

Luckily this can be solved by adding 1 simple logic, [found here](https://stackoverflow.com/questions/33692599/how-can-i-cancel-an-ongoing-request-in-gmsplacesclient-autocompletequery). We can modify our reverse geocoding helper function to entertain the last request only and ignore all outstanding stale requests. Here is the code.

&nbsp;

<iframe 
 width="100%"
 height="600" 
 src="data:text/html;charset=utf-8,
 <head><base target='_blank' /></head>
 <body><script src='https://gist.github.com/mzeeshanid/c5ee11295f18569bd746331f1efef681.js'></script>
 </body>">
 
&nbsp;

Enjoy!

The process of converting latitude and longitude into human-readable addresses is called Reverse GeoCoding. If you are using GMSGeocoder for reverse geocoding then you might find yourself lost in case you need to cancel the ongoing request.

large_geojango-maps-Z8UgB80_46w-unsplash.jpg

medium_geojango-maps-Z8UgB80_46w-unsplash.jpg

small_geojango-maps-Z8UgB80_46w-unsplash.jpg

thumbnail_geojango-maps-Z8UgB80_46w-unsplash.jpg

geojango-maps-Z8UgB80_46w-unsplash.jpg

GMSGeocoder cancel ongoing request workaround

Muhammad Zeeshan

&nbsp;

[**Cocoapods**](https://cocoapods.org/) is a popular dependency manager among iOS developers. iOS developers often use Cocoapods for integrating third party libraries. It provides [**different hooks**](https://guides.cocoapods.org/syntax/podfile.html#group_hooks) to perform certain custom actions. For example, [**post install**](https://guides.cocoapods.org/syntax/podfile.html#post_install) hook will be invoked every time dependencies are resolved. Cocoapods is built with [**Ruby**](https://www.ruby-lang.org/) which is compatible with the preinstalled version of Ruby in Mac. In this article we are going to explore how can we write a custom script for automating certain actions. As Cocoapods is built with Ruby, we can use the [Ruby language](https://www.ruby-lang.org/) syntax and features to write custom scripts. 

## Real scenario:

Let say, you are using a newer version of Xcode i.e. 12 or later and you have some old dependencies to resolve and the author of the library did not update the minimum deployment target in the podspec file then you may experience the following error after running ```pod install```. If you are developing an app for react native then most likely you will experience this issue.

&nbsp;

> The iOS Simulator deployment target ‘IPHONEOS_DEPLOYMENT_TARGET’ is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.4.99. (in target ‘CocoaLibEvent’ from project ‘Pods’)

&nbsp;

One way around is to go to each target's settings and update its deployment target manually. This way will become cumbersome if you have a large number of dependencies. Moreover, this way will become painful if you run ```pod install``` more often.

&nbsp;

![{"alt" : "Manual steps for updating deployment target","width": 961,"height": 501,"thumb": "https://dzm9gzl83npws.cloudfront.net/thumbnail_1_v_I_Rs_E_Z8_Kv_C_Mch2m9pf_Snw_2c49babc8a.jpg"}](https://dzm9gzl83npws.cloudfront.net/1_v_I_Rs_E_Z8_Kv_C_Mch2m9pf_Snw_2c49babc8a.jpg)


## Custom Script In Action:

A better way is to use post install hook for Cocoapods to update the target’s minimum deployment target. Whenever you run the pod install Cocoapod’s post installation hook will be invoked after resolving dependencies and here it provides the opportunity to perform custom actions using a custom script. The syntax for post installation hook is:

&nbsp;

```
post_install do |installer|
	#custom script for execution
end
```

&nbsp;

You need to put the above block inside the target's block. 

&nbsp;

Then we need to iterate all dependencies which can be done as follows:

&nbsp;

```
installer.pods_project.targets.each do |target|
	#block for iterating each target
end
```

&nbsp;

Next, we need to read the configuration settings for each target, inside the target iterator block above.

&nbsp;

```
target.build_configurations.each do |config|
	#here configuration settings of the target
end
```

&nbsp;

Next, we will read the deployment target and save it in a variable to use in the next step.

&nbsp;

```
deployment_target = config.build_settings['IPHONEOS_DEPLOYMENT_TARGET']
```

&nbsp;

The deployment target is a string so need to convert it into an integer for comparision. So in the next step, we will convert string into an array of characters. Before moving forward, we will add a condition for safety to make sure that the converted array has atleast 1 element to prevent the script from crashing. Then we will convert the first element into integer and compare in order to make sure that it should be greater than 9.

&nbsp;

```
target_components = deployment_target.split

if target_components.length > 0
 target_initial = target_components[0].to_i
 if target_initial < 9
 config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = "9.0"
 end
end
```

&nbsp;

If we consolidate all the above steps, the script will look like this:

&nbsp;

<iframe 
 width="100%"
 height="500" 
 src="data:text/html;charset=utf-8,
 <head><base target='_blank' /></head>
 <body><script src='https://gist.github.com/mzeeshanid/ec4989d14d92d1af7a64c803f474d553.js'></script>
 </body>">

&nbsp;

Inside the pod file, the script should look like the following screenshot:

&nbsp;

![{"alt" : "Screenshot for final look of podspec file","width": 1229,"height": 861,"thumb": "https://dzm9gzl83npws.cloudfront.net/thumbnail_1_yps_XX_Lm9_S4_CR_Qq3_Vku_Y8h_Q_160f68416a.jpg"}](https://dzm9gzl83npws.cloudfront.net/1_yps_XX_Lm9_S4_CR_Qq3_Vku_Y8h_Q_160f68416a.jpg)

&nbsp;

Now run the pod install in the terminal to see it in action 😎🙂

&nbsp;

Cocoapods is a popular dependency manager among iOS developers. iOS developers often use Cocoapods for integrating third party libraries. It provides different hooks to perform certain custom actions.

large_cocoapods_custom_script_24539e2b8a.jpg

medium_cocoapods_custom_script_24539e2b8a.jpg

small_cocoapods_custom_script_24539e2b8a.jpg

thumbnail_cocoapods_custom_script_24539e2b8a.jpg

cocoapods_custom_script_24539e2b8a.jpg

Writing custom script for Cocoapods

I strive to build immerse apps, having more than 6 years of experience in the field of mobile application development specifically for iOS platform using objective-c and swift programming language.

Muhammad Zeeshan

iOS

mzeeshanid@yahoo.com