Accessing CDNs in Your Own Code

A couple of cases where we've done so:

• automatically generating archvies and uploading them to S3
• writing a migration utility to compare two CDN locations and copy selected files between them
• clearing out a CDN after doing tests on stage

This section describes the public API of the CDN library, which takes care of things like ensuring filename uniqueness, figuring out how to move files between different CDNs, and handling user uploads. Note that ALL public functions are prefixed with "io" to avoid conflicts with existing CFML functions.

You can access these function at application.fc.lib.cdn.

ioFileExists

Does what it says on the box. Checks a single location to see if a file exists.

<cfif application.fc.lib.cdn.ioFileExists(location="cache",file=sCacheFileName)>
    <cfreturn sCacheFileName />
</cfif>

ioFindFile

Searches the provided locations, and returns the first that contains the specified file, or an empty string if there isn't any.

<cfset currentLocation = application.fc.lib.cdn.ioFindFile(locations="privatefiles,publicfiles",file=arguments.stObject[arguments.stMetadata.name]) />

ioGetUniqueFilename

Returns a version of the specified filename which is unique among every listed location by appending numbers to the name. Note that it is rare to have to call this function directly, as all functions which put a file into a CDN have options to enforce filename uniqueness. However if you wish to change how FarCry enforces uniqueness, you can override this function in your project.

<cfset moveto = ioGetUniqueFilename(locations="privatefiles,publicfiles",file=newfile) />

ioGetFileSize

Returns the size of the file in bytes.

<cfoutput>Size: <span class="image-size">#round(application.fc.lib.cdn.ioGetFileSize(location="images",file=arguments.stMetadata.value)/1024)#</span>KB</cfoutput>

ioGetFileLocation

Returns serving information for the file. The result is a struct - either: method=redirect + path (URL) OR method=stream + path (local path).

<cfset stImage = application.fc.lib.cdn.ioGetFileLocation(location="images",file=arguments.stMetadata.value) />
<cfoutput><img src="#stImage.path#"></cfoutput>

ioWriteFile

Writes the specified data to a file.

<cfset stResult.filename = application.fc.lib.cdn.ioWriteFile(location="images",file=filename,data=newImage,datatype="image",quality=arguments.quality,nameconflict="makeunique",uniqueamong="images") />

ioReadFile

Reads from the specified file.

<cfimage action="info" source="#application.fc.lib.cdn.ioReadFile(location='images',file=stResult.value,datatype='image')#" structName="stImage" />

ioMoveFile

Moves the specified file between locations. Note that when moving a file between different CDN types, this function moves the file to the local temporary directory, then to the target location from there.

Note that while every argument is marked as optional, in practice you need:

• source_location and source_file OR source_localpath
• dest_location and dest_file OR dest_localpath

<cfset application.fc.lib.cdn.ioMoveFile(source_location="publicfiles",source_file=arguments.stObject[arguments.stMetadata.name],dest_location="privatefiles") />

ioCopyFile

Copies the specified file between locations. Note that when copying a file between different CDN types, this function copies the file to the local temporary directory, then moves it to the target location from there.

Note that while every argument is marked as optional, in practice you need:

• source_location and source_file OR source_localpath
• dest_location and dest_file OR dest_localpath

<cfset application.fc.lib.cdn.ioCopyFile(
    source_location="images",
    source_file=stLocal.stInstance.thumbnail,
    dest_location="archive",
    dest_file="/#stLocal.stInstance.typename#/#stLocal.stProps.archiveID#_thumb.#ListLast(stLocal.stInstance.thumbnail,'.')#"
) />

ioUploadFile

Uploads the a file to the specified location.

<cfset stResult.value = application.fc.lib.cdn.ioUploadFile(
    location="securefiles",
    destination=arguments.stMetadata.ftDestination,
    field="#stMetadata.FormFieldPrefix##stMetadata.Name#New",
    nameconflict="makeunique",
    uniqueamong="privatefiles,publicfiles",
    acceptedextensions=arguments.stMetadata.ftAllowedFileExtensions
) />

ioDeleteFile

Deletes the specified file.

<cfset application.fc.lib.cdn.ioDeleteFile(location="images",file="/#arguments.stObject[arguments.stMetadata.name]#") />

ioDirectoryExists

Checks that a specified directory exists. All functions which write to a CDN use this function to check whether the target directory needs to be created first.

<cfset application.fc.lib.cdn.ioDeleteFile(location="images",file="/#arguments.stObject[arguments.stMetadata.name]#") />

ioDirectoryExists

Checks that a specified directory exists. All CDN functions which create a file already perform internal checks to find out if a directory needs to be created first. As a result, there is no example in core of a call to this function.

<cfif application.fc.lib.cdn.ioDirectoryExists(location="images",file="/#stMetadata.ftDestination#")>
    <!--- something here --->
</cfif>

ioCreateDirectory

Creates the specified directory, including parent directories. All CDN functions which create a file already perform internal checks and create directories as necessary. As a result, there is no example in core of a call to this function.

<cfset application.fc.lib.cdn.ioCreateDirectory(location="images",file="/#stMetadata.ftDestination#") />

ioGetDirectoryListing

Returns a query containing the files under the specfied directory. The resulting query has a single field "file", which is the full path as would be passed into the other CDN functions. The results are recursive and do not include directories, except by implication.

It is worth noting that the "images" location is unusual in that it usually corresponds to the project WWW directory, and so a naive query to the "images" location will return everything in the webroot. In practice, listings of "images" should be filtered by /images.

<cfset qSourceFiles = application.fc.lib.cdn.ioGetDirectoryListing(location=form.source_location,dir=form.source_filter) />
<cfset qTargetFiles = application.fc.lib.cdn.ioGetDirectoryListing(location=form.target_location,dir=form.target_filter) />            

<cfset stFound = structnew() />
<cfloop query="qSourceFiles">
    <cfif not structkeyexists(stFound,qSourceFiles.file)>
        <cfset stFound[qSourceFiles.file] = 1 />
    <cfelse>
        <cfset stFound[qSourceFiles.file] = stFound[qSourceFiles.file] + 1 />
    </cfif>
</cfloop>
<cfloop query="qTargetFiles">
    <cfif not structkeyexists(stFound,qTargetFiles.file)>
        <cfset stFound[qTargetFiles.file] = 2 />
    <cfelse>
        <cfset stFound[qTargetFiles.file] = stFound[qTargetFiles.file] + 2 />
    </cfif>
</cfloop>

<cfloop collection="#stFound#" item="thisfile">
    <cfset queryaddrow(qFiles) />
    <cfset querysetcell(qFiles,"file",thisfile) />
    <cfset querysetcell(qFiles,"inSource",bitand(stFound[thisfile],1) eq 1) />
    <cfset querysetcell(qFiles,"inTarget",bitand(stFound[thisfile],2) eq 2) />
</cfloop>
            
<cfquery dbtype="query" name="qFiles">select * from qFiles order by file</cfquery>