Two Converging Technological Paradigms and Offer Bottom-Line Value To Any Organization

Microservices Journal

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Microservices Authors: Liz McMillan, Madhavan Krishnan, VP, Cloud Solutions, Virtusa, Jason Bloomberg, Elizabeth White, Don MacVittie

Related Topics: Cloud Computing, Microservices Journal, DevOps Journal

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Web Performance 101: HTTP Headers | @DevOpsSummit #DevOps #WebPerf

Hypertext Transfer Protocol, or HTTP, was first introduced by Tim Berners-Lee in 1991

Web Performance 101: HTTP Headers
By Kameerath Kareem

Hypertext Transfer Protocol, or HTTP, was first introduced by Tim Berners-Lee in 1991. The initial version HTTP/0.9 was designed to facilitate data transfers between a client and server. The protocol works on a request-response model over a TCP connection, but it’s evolved over the years to include several improvements and advanced features. The latest version is HTTP/2, which has introduced major advancements that prioritize webpage performance and speed.

This article discusses an important component of the HTTP model – headers. Before you continue, read this detailed blog post to understand how HTTP works.

What are HTTP headers?
There are three main components that make up the request/response structure. This includes:

  • Start line
  • Headers
  • Body/Content

Based on the type of the HTTP message, the start line includes the method, path, status code, and protocol version. The HTTP headers are added next and defined as name-value pairs separated by a colon. These headers are used to send additional parameters along with the request or response. The body of the message will include the data to be sent with the request or the data received along with the response.

There are different types of headers and we can group these based on its usage into 4 broad categories:

  • General header
  • Request header
  • Response header
  • Entity header

General Headers
Headers that can be used in both requests and response messages and it is independent of the data being exchanged. Some of the common general headers include:

Cache-Control
Cache-Control is a general header type that can be used to specify caching preference during the response-request cycle. The directives specified in the header must be strictly implemented when caching by the client and server.

For example, to cache a static file on a webpage, you can define the header using the format below:

Cache-Control: public, max-age=31536000

Cache Request max-stale[=<seconds>] Cache Response must-revalidate
max-age=<seconds> no-cache
min-fresh=<seconds> no-store
no-cache no-transform
no-store public
no-transform private
only-if-cached proxy-revalidate
max-age=<seconds>
s-maxage=<seconds>
  • max-stale: Client accepts expired content and allows you to configure responses expire time in seconds.
  • max-age: Specifies the maximum time for which a resource is considered as fresh.
  • min-fresh: Client expects a response that’s fresh for at least the specified number of seconds.
  • no-cache: The server must validate the cache content before sending it to client.
  • no-store: The cache is not allowed to store the request and response data.
  • no-transform: The cache should not transform the stored content. For example, changing the image format to save space.
  • only-if-cached: The client requires only cached content and the request does not check with the origin server for fresh content.
  • must-revalidate: The fetched resource must be validated to ensure it is not stale.
  • public: The response can be cached anywhere – private or shared cache.
  • private: The response must be stored in private cache; shared caching is not allowed.
  • proxy-revalidate: Applies to shared caches, the response must be validated for freshness.

There are a few other header directives that are not part of the HTTP caching standards. These are called Extension Cache-Control directives, immutable is an example. The immutable directive indicates that the response body will remain unchanged so the client need not validate the content again.

Connection
The Connection header specifies if the HTTP connection should remain open once the data exchange has completed. It sets up a persistent connection, which can be reused by subsequent requests.

To keep the connection open, the header is sent in the following format:

Connection: keep-alive

The header directives include:

  • Keep-alive: The connection is persistent and once established, it remains open for all subsequent requests.
  • Close: This value instructs the client or server to close the connection.

Transfer-Encoding
The Transfer-Encoding specifies the format or encoding to be used when transferring the content in the body of the message. For example, to indicate the file should be compressed the header is sent in the following format:

Transfer-Encoding: compress

You can also specify multiple encoding formats separated by comma. The directives for this header include:

  • chunked: The content is split into chunks before transferring it to the client or server.
  • deflate: The content is compressed using deflate compression algorithm.
  • gzip: This is another compression format based on the UNIX gzip program.
  • identity: Indicates the content doesn’t need compression or modification.

Request Header
These headers define parameters for the data requested or parameters that give important information about the client making the request. Some of the common request headers include:

Accept-encoding
This request header specifies the encoding that the client supports. For example, to indicate the client understands multiple encoding, the header format will be:

Accept-Encoding: deflate, gzip;q=1.0, *;q=0.5

The values accepted by the header are:

  • gzip
  • compress
  • deflate
  • br (Brotli algorithm)
  • identity
  • * (default header value)
  • ;q= (qvalues weighting)

If-match
The If-match request header indicates a conditional request. The header returns the requested response only if it matches the ETag (a unique identifier for a resource) or list of ETag values specified in the header.

For example:  To return a resource from the server that has any of the following ETags, the header will be in the following format (where “W/” indicates a weak ETag value that may not match byte for byte).

If-Match: W/”67ab43″, “54ed21”, “7892dd”

If-modified-since
The header is another conditional request. The server will return the requested resource only if it has been modified after the specified date. If-Modified-Since is used only with a GET or HEAD request. For example: to return a request that was modified after October 1, the header is sent in this format:

If-Modified-Since: Sun, 1 Oct 2017 01:28:00 GMT

The request header accepts the following values in the date parameter:

If-Modified-Since: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT

Range
The Range header specifies the part of the document/resource to be returned. It can be used to request partial content split into different ranges or just a single section of the content. For example: to get the data between a specific number of bytes, the header format will be:

Range: bytes=200-1000, 2000-6576

To request from multiple parts of the same content, the header should be in the following format:

Range: <unit>=<range-start>-<range-end>, <range-start>-<range-end>, <range-start>-<range-end>

User-Agent
The User-Agent request header provides details about the client application including the software version, application type, operating system etc. The common user-agent header request will be in the following format:

User-Agent: Mozilla/<version> (<system-information>) <platform> (<platform-details>) <extensions>

Here is an example of a FireFox user agent string:

Mozilla/5.0 (platform; rv:geckoversion) Gecko/geckotrail Firefox/firefoxversion

The post Web Performance 101: HTTP Headers appeared first on Catchpoint's Blog - Web Performance Monitoring.

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DevOps at Cloud Expo taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world.

Must Watch Video: Recap of @DevOpsSummit New York Javits Center

The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.

Nutanix DevOps Booth at @DevOpsSummit New York Javits Center

DevOps at Cloud Expo will expand the DevOps community, enable a wide sharing of knowledge, and educate delegates and technology providers alike. Recent research has shown that DevOps dramatically reduces development time, the amount of enterprise IT professionals put out fires, and support time generally. Time spent on infrastructure development is significantly increased, and DevOps practitioners report more software releases and higher quality. Sponsors of DevOps at Cloud Expo will benefit from unmatched branding, profile building and lead generation opportunities through:

  • Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers.
  • Showcase exhibition during our new extended dedicated expo hours
  • Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35 minute technical session
  • Online advertising in SYS-CON's i-Technology Publications
  • Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage.
  • Unprecedented PR Coverage: Editorial Coverage on DevOps Journal
  • Tweetup to over 75,000 plus followers
  • Press releases sent on major wire services to over 500 industry analysts.

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez by email at events (at) sys-con.com, or by phone 201 802-3021.

Most Popular Video: Sheng Liang's Containers Talk

@DevOpsSummit at Cloud Expo taking place October 31 - November 2, 2017, Santa Clara Convention Center, CA, and is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.

@DevOpsSummit 2017 Silicon Valley
(October 31 - November 2, 2017, Santa Clara Convention Center, CA)

@DevOpsSummit 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend 21st Cloud Expo, October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.

Track 1. Enterprise Cloud | Cloud-Native
Track 2.
Big Data | Analytics
Track 3. Internet of Things | IIoT | Smart Cities

Track 4. DevOps | Digital Transformation (DX)

Track 5. APIs | Cloud Security | Mobility

Track 6.
AI | ML | DL | Cognitive
Track 7.
Containers | Microservices | Serverless
Track 8. FinTech | InsurTech | Token Economy

Speaking Opportunities

The upcoming 21st International @CloudExpo@ThingsExpo, October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY announces that its Call For Papers for speaking opportunities is open. Themes and topics to be discussed include:

  • Agile
  • API management
  • APM
  • Application delivery
  • Cloud development
  • Configuration automation
  • Containers
  • Continuous delivery
  • Continuous integration
  • Continuous testing
  • DevOps anti-patterns
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  • DevOps system architecture
  • Docker
  • Enterprise DevOps
  • Identity and access
  • IT orchestration
  • Kubernetes
  • Load testing
  • Microservices
  • Mobile DevOps
  • Monitoring
  • Network automation
  • Quality assurance
  • Release automation
  • Serverless
  • Scrum
  • Service virtualization
  • Teaming
  • Test automation
  • WebOps, CloudOps, ChatOps, NoOps

Submit your speaking proposal today! ▸ Here

Cloud Expo | @ThingsExpo 2017 Silicon Valley
(October 31 - November 2, 2017, Santa Clara Convention Center, CA)

Cloud Expo | @ThingsExpo 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

Download Show Prospectus ▸ Here

Every Global 2000 enterprise in the world is now integrating cloud computing in some form into its IT development and operations. Midsize and small businesses are also migrating to the cloud in increasing numbers.  

Companies are each developing their unique mix of cloud technologies and services, forming multi-cloud and hybrid cloud architectures and deployments across all major industries. Cloud-driven thinking has become the norm in financial services, manufacturing, telco, healthcare, transportation, energy, media, entertainment, retail and other consumer industries, and the public sector.

Cloud Expo is the single show where technology buyers and vendors can meet to experience and discus cloud computing and all that it entails. Sponsors of Cloud Expo will benefit from unmatched branding, profile building and lead generation opportunities through:

  • Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers.
  • Showcase exhibition during our new extended dedicated expo hours
  • Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35-minute technical session
  • Online advertising in SYS-CON's i-Technology Publications
  • Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage.
  • Unprecedented PR Coverage: Editorial Coverage on Cloud Computing Journal.
  • Tweetup to over 75,000 plus followers
  • Press releases sent on major wire services to over 500 industry analysts.

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez by email at events (at) sys-con.com, or by phone 201 802-3021.

The World's Largest "Cloud Digital Transformation" Event

@CloudExpo | @ThingsExpo 2017 Silicon Valley
(Oct. 31 - Nov. 2, 2017, Santa Clara Convention Center, CA)

@CloudExpo | @ThingsExpo 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

Full Conference Registration Gold Pass and Exhibit Hall ▸ Here

Register For @CloudExpo ▸ Here via EventBrite

Register For @ThingsExpo ▸ Here via EventBrite

Register For @DevOpsSummit ▸ Here via EventBrite

Sponsorship Opportunities

Sponsors of Cloud Expo | @ThingsExpo will benefit from unmatched branding, profile building and lead generation opportunities through:

  • Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers
  • Showcase exhibition during our new extended dedicated expo hours
  • Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35 minute technical session
  • Online targeted advertising in SYS-CON's i-Technology Publications
  • Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage
  • Unprecedented Marketing Coverage: Editorial Coverage on ITweetup to over 100,000 plus followers, press releases sent on major wire services to over 500 industry analysts

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez (@GonzalezCarmen) today by email at events (at) sys-con.com, or by phone 201 802-3021.

Secrets of Sponsors and Exhibitors ▸ Here
Secrets of Cloud Expo Speakers ▸ Here

All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades.

With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo@ThingsExpo, October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-4, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.

Delegates to Cloud Expo | @ThingsExpo will be able to attend 8 simultaneous, information-packed education tracks.

There are over 120 breakout sessions in all, with Keynotes, General Sessions, and Power Panels adding to three days of incredibly rich presentations and content.

Join Cloud Expo | @ThingsExpo conference chair Roger Strukhoff (@IoT2040), October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, for three days of intense Enterprise Cloud and 'Digital Transformation' discussion and focus, including Big Data's indispensable role in IoT, Smart Grids and (IIoT) Industrial Internet of Things, Wearables and Consumer IoT, as well as (new) Digital Transformation in Vertical Markets.

Financial Technology - or FinTech - Is Now Part of the @CloudExpo Program!

Accordingly, attendees at the upcoming 21st Cloud Expo | @ThingsExpo October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, will find fresh new content in a new track called FinTech, which will incorporate machine learning, artificial intelligence, deep learning, and blockchain into one track.

Financial enterprises in New York City, London, Singapore, and other world financial capitals are embracing a new generation of smart, automated FinTech that eliminates many cumbersome, slow, and expensive intermediate processes from their businesses.

FinTech brings efficiency as well as the ability to deliver new services and a much improved customer experience throughout the global financial services industry. FinTech is a natural fit with cloud computing, as new services are quickly developed, deployed, and scaled on public, private, and hybrid clouds.

More than US$20 billion in venture capital is being invested in FinTech this year. @CloudExpo is pleased to bring you the latest FinTech developments as an integral part of our program, starting at the 21st International Cloud Expo October 31 - November 2, 2017 in Silicon Valley, and June 12-14, 2018, in New York City.

@CloudExpo is accepting submissions for this new track, so please visit www.CloudComputingExpo.com for the latest information.

About SYS-CON Media & Events

SYS-CON Media (www.sys-con.com) has since 1994 been connecting technology companies and customers through a comprehensive content stream - featuring over forty focused subject areas, from Cloud Computing to Web Security - interwoven with market-leading full-scale conferences produced by SYS-CON Events. The company's internationally recognized brands include among others Cloud Expo® (@CloudExpo), Big Data Expo® (@BigDataExpo), DevOps Summit (@DevOpsSummit), @ThingsExpo® (@ThingsExpo), Containers Expo (@ContainersExpo) and Microservices Expo (@MicroservicesE).

Cloud Expo®, Big Data Expo® and @ThingsExpo® are registered trademarks of Cloud Expo, Inc., a SYS-CON Events company.

More Stories By Mehdi Daoudi

Catchpoint radically transforms the way businesses manage, monitor, and test the performance of online applications. Truly understand and improve user experience with clear visibility into complex, distributed online systems.

Founded in 2008 by four DoubleClick / Google executives with a passion for speed, reliability and overall better online experiences, Catchpoint has now become the most innovative provider of web performance testing and monitoring solutions. We are a team with expertise in designing, building, operating, scaling and monitoring highly transactional Internet services used by thousands of companies and impacting the experience of millions of users. Catchpoint is funded by top-tier venture capital firm, Battery Ventures, which has invested in category leaders such as Akamai, Omniture (Adobe Systems), Optimizely, Tealium, BazaarVoice, Marketo and many more.