Welcome!

@CloudExpo Authors: Pat Romanski, Liz McMillan, Elizabeth White, William Schmarzo, Yeshim Deniz

Related Topics: @CloudExpo, Mobile IoT, Cloud Security

@CloudExpo: Blog Feed Post

Cross-Domain Security, JSON, JSONP and CORS

Why my REST service doesn’t work

Tiggzi, the cloud-based HTML5, jQuery Mobile and PhoneGap mobile app builder come with a very powerful and easy way to define and consume REST services in a mobile app. Inside the builder, you get what amounts to a very easy to use REST services console where any service can be defined, tested, and have its response parameters automatically defined.

Click image to see larger version

Click image to see larger version

Being able to run and test the service from inside the builder is very important as it demonstrates that the service works and data is returned. The next step is usually to make the service available on the page, define UI-service data binding, and then set the service to be invoked on some event.



But, when testing the app in a browser, the services sometimes doesn’t work or no data is returned. This creates confusion as the service worked when testing it inside the builder but doesn’t work when invoking from a browser page. The reason this happens is because of the cross-domain security built into browsers.

Click image to see larger version

All browsers have this built into them. Basically, to invoke a service via JavaScript (AJAX) from a domain like mydomain.com, the page from which the service is invoked has to be hosted on that same domain, mydomain.com. When testing an app built in Tiggzi, the page is running on tiggzi.com but the service being invoked is on a different domain like, for instance, search.twitter.com. The browser won’t allow this. This is by design to ensure that no bad or malicious JavaScript code can be used to invoke the service.

What can we do? There are a number of options to make this work.

Hosting the page on the same domain

The most obvious option is to host the page and the service on the same domain. The solution is simple but not very practical today. With the new shift to a client-cloud architecture, many services used in mobile apps today are cloud-based, and are hosted via different API providers and thus are on different domains. Hosting the page and the service on the same domain might work well if services were deployed completely within the same organization.

JSONP (JSON with Padding)

JSONP is the unofficial way many provides solve the cross-domain problem. Instead of making a regular AJAX request which is subject to cross-domain security, the request is made via loading a JavaScript file with a special callback function defined. As loading a JavaScript file is not an AJAX call, it doesn’t fall under the cross-domain security problem. The callback function is then invoked to process the data returned (which is JSON). The URL looks like this:

http://someurl?callback=getthedata

getthedata would be invoked to process the response.

With JSONP, a service can be invoked from a page hosted on different domain. For example, Twitter’s API supports JSONP and thus can be invoked from tiggzi.com hosted pages. However, it’s up to the service to support JSONP and not all services support this feature.

Cross-origin resource sharing (CORS)

While JSONP could be considered a hack or a workaround, CORS is an attempt to create a standard way to solve the cross-domain issue. When a service request is made, the server will include a header parameter in the response indicating that the domain from which the call was made – is allowed to invoke this service. However, it’s up to the service providers to add such support. For example, the Parse mobile back-end service supports this feature and makes it very easy to use their services.

Tiggzi proxy

If none of the above options are available, Tiggzi Mobile App Builder provides a proxy service that works for testing and apps that are hosted on tiggzi.net. When using the proxy, the request is first sent to the proxy server and then, from the server, the request is made to the service. Because the request is sent from the server and not from the page, cross-domain security is not triggered.

Google Chrome with security disabled

Finally, one more option exists, but it’s only useful in development or testing. You can start Google Chrome with security disabled in which case the cross-domain issue is no longer a problem. To start Chrome with security disabled start it with this command line:

chrome –disable-web-security

Mobile Web app vs. mobile app

Everything I just described applies to mobile Web apps – pure Web apps running in the browser. When you develop a PhoneGap app (hybrid app) cross-domain security is not an issue, even though the app is actually running in a browser (albeit a chromeless one).

Next time you are trying a REST service, this should help you understand that’s really happening.

More Stories By Max Katz

Max Katz heads Developer Relations for Appery.io, a cloud-based mobile app platform. He loves trying out new and cool REST APIs in mobile apps. Max is the author of two books “Practical RichFaces” (Apress 2008, 2011), DZone MVB (Most Valuable Blogger), and is a frequent speaker at developer conferences. You can find out what Max is up to on his blog: http://maxkatz.org and Twitter: @maxkatz.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@CloudExpo Stories
In his session at 20th Cloud Expo, Mike Johnston, an infrastructure engineer at Supergiant.io, discussed how to use Kubernetes to set up a SaaS infrastructure for your business. Mike Johnston is an infrastructure engineer at Supergiant.io with over 12 years of experience designing, deploying, and maintaining server and workstation infrastructure at all scales. He has experience with brick and mortar data centers as well as cloud providers like Digital Ocean, Amazon Web Services, and Rackspace. H...
The question before companies today is not whether to become intelligent, it’s a question of how and how fast. The key is to adopt and deploy an intelligent application strategy while simultaneously preparing to scale that intelligence. In her session at 21st Cloud Expo, Sangeeta Chakraborty, Chief Customer Officer at Ayasdi, will provide a tactical framework to become a truly intelligent enterprise, including how to identify the right applications for AI, how to build a Center of Excellence to ...
You know you need the cloud, but you’re hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You’re looking at private cloud solutions based on hyperconverged infrastructure, but you’re concerned with the limits inherent in those technologies.
SYS-CON Events announced today that Massive Networks will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Massive Networks mission is simple. To help your business operate seamlessly with fast, reliable, and secure internet and network solutions. Improve your customer's experience with outstanding connections to your cloud.
DevOps is under attack because developers don’t want to mess with infrastructure. They will happily own their code into production, but want to use platforms instead of raw automation. That’s changing the landscape that we understand as DevOps with both architecture concepts (CloudNative) and process redefinition (SRE). Rob Hirschfeld’s recent work in Kubernetes operations has led to the conclusion that containers and related platforms have changed the way we should be thinking about DevOps and...
As businesses adopt functionalities in cloud computing, it’s imperative that IT operations consistently ensure cloud systems work correctly – all of the time, and to their best capabilities. In his session at @BigDataExpo, Bernd Harzog, CEO and founder of OpsDataStore, presented an industry answer to the common question, “Are you running IT operations as efficiently and as cost effectively as you need to?” He then expounded on the industry issues he frequently came up against as an analyst, and ...
SYS-CON Events announced today that Datera, that offers a radically new data management architecture, has been named "Exhibitor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Datera is transforming the traditional datacenter model through modern cloud simplicity. The technology industry is at another major inflection point. The rise of mobile, the Internet of Things, data storage and Big...
Everything run by electricity will eventually be connected to the Internet. Get ahead of the Internet of Things revolution and join Akvelon expert and IoT industry leader, Sergey Grebnov, in his session at @ThingsExpo, for an educational dive into the world of managing your home, workplace and all the devices they contain with the power of machine-based AI and intelligent Bot services for a completely streamlined experience.
Because IoT devices are deployed in mission-critical environments more than ever before, it’s increasingly imperative they be truly smart. IoT sensors simply stockpiling data isn’t useful. IoT must be artificially and naturally intelligent in order to provide more value In his session at @ThingsExpo, John Crupi, Vice President and Engineering System Architect at Greenwave Systems, will discuss how IoT artificial intelligence (AI) can be carried out via edge analytics and machine learning techn...
FinTechs use the cloud to operate at the speed and scale of digital financial activity, but are often hindered by the complexity of managing security and compliance in the cloud. In his session at 20th Cloud Expo, Sesh Murthy, co-founder and CTO of Cloud Raxak, showed how proactive and automated cloud security enables FinTechs to leverage the cloud to achieve their business goals. Through business-driven cloud security, FinTechs can speed time-to-market, diminish risk and costs, maintain continu...
Existing Big Data solutions are mainly focused on the discovery and analysis of data. The solutions are scalable and highly available but tedious when swapping in and swapping out occurs in disarray and thrashing takes place. The resolution for thrashing through machine learning algorithms and support nomenclature is through simple techniques. Organizations that have been collecting large customer data are increasingly seeing the need to use the data for swapping in and out and thrashing occurs ...
SYS-CON Events announced today that CA Technologies has been named "Platinum Sponsor" of SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business - from apparel to energy - is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the applic...
As many know, the first generation of Cloud Management Platform (CMP) solutions were designed for managing virtual infrastructure (IaaS) and traditional applications. But that’s no longer enough to satisfy evolving and complex business requirements. In his session at 21st Cloud Expo, Scott Davis, Embotics CTO, will explore how next-generation CMPs ensure organizations can manage cloud-native and microservice-based application architectures, while also facilitating agile DevOps methodology. He wi...
From 2013, NTT Communications has been providing cPaaS service, SkyWay. Its customer’s expectations for leveraging WebRTC technology are not only typical real-time communication use cases such as Web conference, remote education, but also IoT use cases such as remote camera monitoring, smart-glass, and robotic. Because of this, NTT Communications has numerous IoT business use-cases that its customers are developing on top of PaaS. WebRTC will lead IoT businesses to be more innovative and address...
Blockchain is a shared, secure record of exchange that establishes trust, accountability and transparency across business networks. Supported by the Linux Foundation's open source, open-standards based Hyperledger Project, Blockchain has the potential to improve regulatory compliance, reduce cost as well as advance trade. Are you curious about how Blockchain is built for business? In her session at 21st Cloud Expo, René Bostic, Technical VP of the IBM Cloud Unit in North America, will discuss th...
While some vendors scramble to create and sell you a fancy solution for monitoring your spanking new Amazon Lambdas, hear how you can do it on the cheap using just built-in Java APIs yourself. By exploiting a little-known fact that Lambdas aren’t exactly single-threaded, you can effectively identify hot spots in your serverless code. In his session at @DevOpsSummit at 21st Cloud Expo, Dave Martin, Product owner at CA Technologies, will give a live demonstration and code walkthrough, showing how ...
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the applic...
Cloud adoption is often driven by a desire to increase efficiency, boost agility and save money. All too often, however, the reality involves unpredictable cost spikes and lack of oversight due to resource limitations. In his session at 20th Cloud Expo, Joe Kinsella, CTO and Founder of CloudHealth Technologies, tackled the question: “How do you build a fully optimized cloud?” He will examine: Why TCO is critical to achieving cloud success – and why attendees should be thinking holistically ab...
As more and more companies are making the shift from on-premises to public cloud, the standard approach to DevOps is evolving. From encryption, compliance and regulations like GDPR, security in the cloud has become a hot topic. Many DevOps-focused companies have hired dedicated staff to fulfill these requirements, often creating further siloes, complexity and cost. This session aims to highlight existing DevOps cultural approaches, tooling and how security can be wrapped in every facet of the bu...
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...