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Techpearl is the best software company in India, we expert in developing customized applications as per client's requirement. We enabled our clients to transform into techsavvy using our state of art technologies.

As a trusted technology solutions partner for a variety of companies worldwide, Techpearl builds innovative software to solve real world problems. Whether the goal is to develop new products, automate existing processes, transition products to newer technologies – our solutions and adaptive strategies will provide the targeted results beyond expectations.

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Looking for a mobile app development company  in India at affordable prices? Then Techpearl must be your choice. We work on all the latest technologies, Android, iOS, Hybrid platforms.  ionic Framework, AWS Serverless, Python, Django, NodeJS, Ruby On Rails, AngularJS, SQL Server, MySQL, PostgreSQL, DynamoDB, MongoDB, Wordpress. 

When a cross origin request is initiated by a client app, Browsers make a preflight request before executing an actual request.

Example: Assume that example.com makes an authenticated POST request to a server api.service.com. The browser makes an additional OPTIONS request to api.service.com before making the actual request.

The POST request will be processed only if the response to the OPTIONS call has the headers

access-control-allow-methods:POST access-control-allow-origin:example.com

If these headers are not present, the POST call is aborted.

Preflight requests make CORS (Cross Origin Resource Sharing) secure, but at the same time they introduce noticeable latency to every rest API call.

This article explains how to avoid OPTIONS calls when you are using AWS cloudfront as CDN and AWS API Gateway to manage your APIs.

Prerequisites

AWS account.

Web Application hosted in AWS Cloudfront.

APIs managed by AWS API Gateway.

Steps 1. Create/Add an Origin in your cloudfront distribution.

a. Navigate to AWS API Gateway, select your API and click on ‘Stages’ from side menu, select any stage and copy invoke url excluding stage name.

b. Navigate to AWS Cloudfront, select your distribution and click on tab ‘Origins and Origin Groups’ then ‘Create Origin’ c. Paste invoke url copied from API Gateway in ‘Origin Domain Name’ d. Leave ‘Origin Path’ empty. e. Change ‘Origin Protocol Policy’ to HTTPS Only. f. Leave the rest of the fields untouched to their default values and click on ‘Create’.

Create origin

2. Create/Add a new Behaviour in your cloudfront distribution.

a. Select your cloudfront distribution and click on “Behaviours” tab and select ‘Create Behaviour’. b. Fill ‘Path Pattern’ with stage name part of your API Gateway invoke url like below /stageName/* c. For ‘Origin or Origin Group’ choose Origin which you have created in Step 1. d. Change ‘Viewer Protocol Policy’ to Redirect HTTP to HTTPS. e. Change Allowed HTTP Methods to GET, HEAD, OPTIONS, PUT, POST, PATCH, DELETE f. In ‘Cached HTTP Methods’ select  OPTIONS g. In ‘Cache Based on Selected Request Headers’ select ‘Whitelist’ Whitelist all the headers which you are referring in your api business logic h. In ‘Object Caching’ select Customize     Enter 0 for Minimum TTL     Enter 0 for Maximum TTL     Enter 0 for Default TTL i. Select ‘All’ for Forward Cookies j. Select ‘Forward all, cache based on all’ for ‘Query String Forwarding and   Caching’ k. Select ‘No’ for ‘Smooth Streaming’ l. Select ‘No’ for ‘Restrict Viewer Access (Use Signed URLs or Signed Cookies)’ m. Select ‘Yes’ for Compress Objects Automatically n. Click ‘Create Behaviour’

3. Test the Setup

Amazon CloudFront is a web service that speeds up the distribution of static and dynamic web content, such as html, css, javascript, and image files.

This document will cover the steps to host an angular website using AWS CloudFront.

Permissions Needed 1. S3 Permission 2. CDN Permission 3. AWS Certificate Manager Permission

Steps to configure CDN

1. Create an S3 bucket named webhost

       a. Create Index.html with the following content        i. <div style="text-align:center"> You have successfully completed your website hosting! </div>        b. Upload index.html to the S3 bucket

2. Configure the bucket for Web Hosting

       a. Select the bucket

       b. Select “Properties”

       c. Select “Static web hosting”

               i. For Index document enter index.html (Angular prod build generates index.html as the starting point for the website)

               ii. For Error document enter error.html (create a file called error.html to show a custom error message when users access a wrong URL)

3. Set Bucket policy There are two possible options        a. Make the bucket public        b. If a custom policy is set, then make the content of the bucket publicly accessible. Refer to this document to set bucket policy

4. Create Cloudfront Distribution        a. Select services  from the top menu        b. Select CloudFront        c. Select Create Distribution.        d. Select Get started under “Web”

Set “Origin Domain name” as the Endpoint of Static website hosting (Step No 2)

Compress Objects Automatically – Select “Yes” for a better performance

CNAME – website name. (Optional, use this for user-friendly website name) If alternate domain is used, an ACM (AWS Certificate Manager) certificate has to be created

Refer to this document to create ACM.

In the above image, set the “Default Root Object” to index.html

5. Click “Create Distribution”. 6. Map CNAMEs and Domain in Route 53 or any other DNS provider.

7. Type your domain in the address bar of the browser. You should see the following result.