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As a follow up on last weeks post about an incompatibility between Railo and Adobe when reading a remote file. Today I am going to demonstrate how I use bit.ly to generate the QR Code on my article print view.
As it turns out ColdFusion and bitly make it very easy to generate and output a QR Code. I have broken it down into four steps.
Step 1: Create A Bit.ly Account And Create A Component Named Bitly.cfc
Before we can get started we first need to create an account with bitly. Once the account is created you will get a username and api key.
With these now create a component named bitly.cfc and create the following initialization function in it. The use of the third argument will become clear later on.
<cffunction name="init" output="false">
<cfargument name="username" required="true" type="string">
<cfargument name="apikey" required="true" type="string">
<cfargument name="isRailo" required="false" type="boolean" default="0" hint="Set to 1 if running on railo">
<cfset variables.username = arguments.username>
<cfset variables.apikey = arguments.apikey>
<cfset variables.isRailo = arguments.isRailo>
<cfreturn this>
</cffunction>
Step 2: Shorten The Url
With the component setup we must now create another function in the bitly component that can take the original long url and shorten it using the bit.ly api.
<cffunction name="getShortUrl" access="public" output="false" returnType="string"
hint="Take a long url to a webpage and compress using the bit.ly service">
<cfargument name="longURL" required="true" type="string" hint="The full url that must be shortened">
<cfset var requestUrl = "">
<cfset var cfhttpResult = "">
<cfset var xmlObject = "">
<cfset var shortUrl = "">
<!--- Build the request string to send to the bit.ly service --->
<cfset requestUrl = "http://api.bit.ly/v3/shorten?login=#variables.username#&apiKey=#variables.apikey#&longUrl=#longURL#&format=xml">
<!--- Call the bit.ly service --->
<cfhttp url="#requestUrl#" method="get" result="cfhttpResult" />
<!--- If a good response --->
<cfif cfhttpResult.StatusCode EQ '200 OK'>
<!--- Parse the filecontent string into an xml object --->
<cfset xmlObject=xmlParse(cfhttpResult.filecontent)>
<!--- Extract the shortened url --->
<cfset shortUrl = xmlObject[1].response.data.url.xmltext>
</cfif>
<cfreturn shortUrl>
</cffunction>
Step 3: Get The QR Code Binary For The Shortened Url
When bit.ly creates a shortened url it also creates a QR Code for it automatically. All we need to do now is read it using cfhttp. The QR Code is accessed using this address pattern:
Plugging this into a function in our bitly component we get this. Note how the isRailo flag is used to deal with the previously discussed incompatibility between ACF and Railo.
<cffunction name="getQRCodeFromShort" access="public" output="false" returnType="any">
<cfargument name="shortUrl" required="true" type="string" hint="The shortened url">
<cfset var cfhttpResult = "">
<cfset var returnImage = "">
<!--- Call the bit.ly service --->
<cfhttp url="#shortURL#.qrcode" result="cfhttpResult"/>
<!--- If a good response --->
<cfif cfhttpResult.StatusCode EQ '200 OK'>
<cfif variables.isRailo>
<!--- Omit the toByteArray() call if running on Railo --->
<cfset returnImage = cfhttpResult.fileContent/>
<cfelse>
<!--- Call toByteArray if running on Adobe ColdFusion --->
<cfset returnImage = cfhttpResult.fileContent.toByteArray() />
</cfif>
</cfif>
<cfreturn returnImage>
</cffunction>
Step 4: Output The QR Code To The Browser
Finally with the byte array of the qr code image returned we need to output it to the screen. This is done with a simple call to cfimage.
You will notice that I am doing a check to see that the qrcode bytearray is not empty (i.e. The service request succeeded). I am using toString() to convert the bytearray value into a simple string that CF can compare against an empty string.
<!--- Test that a non empty string is returned for the qr code binary --->
<cfif toString(qrcodeBinary) NEQ "">
<!--- Use cfimage to output the qr code to the browser --->
<cfimage action="writeToBrowser" source="#qrcodeBinary#" />
</cfif>
Putting It All Together
Finally we can test our completed bitly component and output method.
<cfset longUrl = "http://www.mydomain.com">
<cfset urlshortner = createObject("component","bitly").init(
username = {your bitly username}
,apikey = {your api key}
,isRailo = 0 {set to 1 if running on railo}
)>
<!--- Get the short url --->
<cfset shortUrl = urlshortner.getShortUrl(longUrl)>
<!--- Get the qr code binary data --->
<cfset qrcodeBinary = urlshortner.getQRCodeFromShort(shortUrl)>
<cfoutput>
Long Url: #longUrl #<br/>
Shortened Url: #shortUrl#<br/>
QR Code:<br/>
</cfoutput>
<!--- Test that a non empty string is returned for the qr code binary --->
<cfif toString(qrcodeBinary) NEQ "">
<!--- Use cfimage to output the qr code to the browser --->
<cfimage action="writeToBrowser" source="#qrcodeBinary#" />
</cfif>
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