Adobe 38043740 Developing Applications - Page 1251

Resolving conflicting filenames, Controlling the type of file uploaded, Error, Overwrite, MakeUnique

Page 1251 highlights

DEVELOPING COLDFUSION 9 APPLICATIONS Using External Resources 1246 Code nameConflict="overwrite" fileField="Form.FiletoUpload"> You uploaded #cffile.ClientFileName#.#cffile. ClientFileExt# successfully to #cffile.ServerDirectory#. Description If the file exists, overwrite it. Specify the name of the file to upload. Do not enclose the variable in number signs. Inform the user of the file that was uploaded and its destination. For information on scope variables, see "Evaluating the results of a file upload" on page 1247. Note: This example performs no error checking and does not incorporate any security measures. Before deploying an application that performs file uploads, ensure that you incorporate both error handling and security. For more information, see "Securing Applications" on page 339 and "Handling Errors" on page 275. Resolving conflicting filenames When you save a file to the server, a file with the same name could exist. To resolve this problem, assign one of these values to the nameConflict attribute of the cffile tag: Error (default) ColdFusion stops processing the page and returns an error. The file is not saved. Skip Allows custom behavior based on file properties. The tag does not save the file or return an error. Overwrite Overwrites a file that has the same name as the uploaded file. MakeUnique Generates a unique filename for the uploaded file. The name is stored in the file object variables serverFile and serverFileName. You can use this variable to record the name used when the file was saved. The unique name might not resemble the attempted name. For more information on file upload status variables, see "Evaluating the results of a file upload" on page 1247. Controlling the type of file uploaded For some applications, you could want to restrict the type of file that is uploaded, for example, to not accept graphic files in a document library. You use the accept attribute to restrict the type of file that you allow in an upload. When an accept qualifier is present, the uploaded file MIME content type must match the criteria specified or an error occurs. The accept attribute takes a comma-separated list of MIME data names, optionally with wildcards. The browser determines the file MIME type. Common types, such as image/gif and text/plain, are registered in the browser. Note: Current versions of Microsoft Internet Explorer and Netscape support MIME type associations. Other browsers and earlier versions might ignore these associations. ColdFusion saves any uploaded file if you omit the accept attribute or specify "*/*". You can restrict the file types, as demonstrated in the following examples. The following cffile tag saves an image file only if it is in the GIF format: The following cffile tag saves an image file only if it is in GIF or JPEG format: Last updated 1/20/2012

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1246
DEVELOPING
COLDFUSION 9 APPLICATIONS
Using External Resources
Las
t
upda
te
d 1/20/2012
Note:
This example performs no error checking and does not incorporate any security measures. Before deploying an
application that performs file uploads, ensure that you incorporate both error handling and security. For more
information, see “
Securing Applications
” on page
339 and “
Handling Errors
” on page
275.
Resolving conflicting filenames
When you save a file to the server, a file with the same name could exist. To resolve this problem, assign one of these
values to the
nameConflict
attribute of the
cffile
tag:
Error
(default) ColdFusion stops processing the page and returns an error. The file is not saved.
Skip
Allows custom behavior based on file properties. The tag does not save the file or return an error.
Overwrite
Overwrites a file that has the same name as the uploaded file.
MakeUnique
Generates a unique filename for the uploaded file. The name is stored in the file object variables
serverFile and serverFileName. You can use this variable to record the name used when the file was saved. The unique
name might not resemble the attempted name. For more information on file upload status variables, see “
Evaluating
the results of a file upload
” on page
1247.
Controlling the type of file uploaded
For some applications, you could want to restrict the type of file that is uploaded, for example, to not accept graphic
files in a document library.
You use the
accept
attribute to restrict the type of file that you allow in an upload. When an
accept
qualifier is
present, the uploaded file MIME content type must match the criteria specified or an error occurs. The
accept
attribute takes a comma-separated list of MIME data names, optionally with wildcards.
The browser determines the file MIME type. Common types, such as image/gif and text/plain, are registered in the
browser.
Note:
Current versions of Microsoft Internet Explorer and Netscape support MIME type associations. Other browsers and
earlier versions might ignore these associations.
ColdFusion saves any uploaded file if you omit the
accept
attribute or specify "*/*". You can restrict the file types, as
demonstrated in the following examples.
The following
cffile
tag saves an image file only if it is in the GIF format:
<cffile action="Upload"
fileField="Form.FiletoUpload"
destination="c:\uploads\"
nameConflict="Overwrite"
accept="image/gif">
The following
cffile
tag saves an image file only if it is in GIF or JPEG format:
nameConflict="overwrite"
If the file exists, overwrite it.
fileField="Form.FiletoUpload">
Specify the name of the file to upload. Do not enclose the variable in number signs.
You uploaded
#cffile.ClientFileName#.#cffile.
ClientFileExt# successfully to
#cffile.ServerDirectory#.
Inform the user of the file that was uploaded and its destination. For information
on scope variables, see “
Evaluating the results of a file upload
” on page
1247.
Code
Description