A number of us are using a private site where we run an application offline. The application offers a download button so that we can take a snapshot of our offline progress, a sort of backup. When we go back on-line we can either upload the the information from the application or we can upload the backup files.
The problem is that whenever we hit the download button we always get the extra dialog asking if we want to save or cancel the file download. This might sound a little ridiculous, but we really do not want to have to move the mouse to the new dialog and have to click the Save button.
The file mime type is application/octet-stream, there is no file extension.
Is there a way to change the Firefox configuration so that this dialog does not appear?
- Application/octet-stream This is the default for binary files. As it means unknown binary file, browsers usually don't execute it, or even ask if it should be executed. They treat it as if the Content-Disposition header was set to attachment, and propose a 'Save As' dialog.
- When IIS locates a file that does not have an extension, the Content-Type that is sent back to the browser is set to application/octet-stream.
- React Sometimes server will provide an interface with application/octet-stream, usually it's related with file operator, so how we handle this using js? Actually it's very easy, make it as a download content will be okay.
I'm trying to get.jpg files from emails. I sent myself an email with a photo. I am using the Idle3 shell. After logging in, the following successfully saves the photo to my computer. What is an OCTET-STREAM file? The OCTET-STREAM format is used for file attachments on the Web with an unknown file type. These.octet-stream files are arbitrary binary data files that may be in any multimedia format.
Thank you.
Apologies, but I have deleted all of the system information gathered automatically because I am not able to submit this request from the machines where the problem occurs.
Those system are:Ubuntu 14:04.3 LTSFirefox 40.0.3
23 November 2017by
Summary
Handling data from Azure Storage blobs is not straightforward. The return value is binary (
application/octet-stream
) at first and needs to be casted into a data type you want to process; in our case into application/json
.This write-up is an easy to follow and real walk through of errors beginners may encounter handling Azure Storage blobs in Azure Logic Apps. It has happened to me.
Requirements
As soon a new file (blob) in an Azure Storage container arrives this file should be processed by an Azure Function app.
Preparing the Playground
1) Create a new Azure Storage Account.
2) Create a new container in the storage account.
3) Create a new Azure Logic App.
4) Design the Logic App.
2) Create a new container in the storage account.
3) Create a new Azure Logic App.
4) Design the Logic App.
Challenges
![What is a application/octet-stream What is a application/octet-stream](/uploads/1/2/6/6/126641320/523071132.png)
A first draft could look like this.
With this configuration we have three steps.
- When one or more blobs are added or modified (metadata only) (Preview)
- Created a connection to the newly created storage account.
- Configured to look in the container
files
. - Configured to look for changes every 10 seconds.
- Get blob content
- Gets the content of a blob by ID. (There is a similar action called “Get blob content using path” if you need to get blob contents via paths.)
- Azure Function
- We call an Azure Function with the content of the blob.
Unfortunately, this configuration does not work because of two errors:
- there is no array of blobs
- data type issues
Trigger & Test the Logic App
I use the Microsoft Azure Storage Explorer to upload files into the container of my Azure Storage account to trigger my Azure Logic App. In every try I increment the number of my test file. The test file contains a simple JSON which can be interpreted by my Azure Function.
After each upload I go back into the Azure Portal to look for new trigger events and shortly afterwards for new run events. To avoid flooding of my trigger history I disable the logic app after each upload to inspect the run results. Before each new try I enable the logic app again.
As you can see our first configuration of the Azure Logic App did not run successfully. Let’s inspect the first error!
Error 1: No Array
The return value of the first step is no array! If we look at the raw data, we see in the
body
that there is no array. Maybe this is an exception because we uploaded only a single file? Try again with two files at the same time.Now, I upload two files at the same time.
Surprisingly, the Logic App gets triggered for each new file separately.
So my assumption was wrong that the action
When one or more blobs are added or modified (metadata only) (Preview)
returns an array. For me the property Number of blobs
was somewhat misleading that the action would return an array.We can resolve this error easily by removing the for-each-loop. We can design the flow of the Logic App in such a way that the Logic App gets triggered for each new or modified blob separately.
Let’s try again by uploading a new file. Again, we see in the run history an error. This time the error is at the third step. The first two steps are running successfully, now. We were successful in getting the content of the blob which has triggered the Logic App. So far, so good! Let’s explore the new error!
Even the raw data of the 2nd step looks fine.
Error 2: Data Type Issues
The Azure Function action in the third step throws the error
UnsupportedMediaType
with the message: “The WebHook request must contain an entity body formatted as JSON.” That error may be confusing at first because our file contains pure JSON data. A look at the content type reveals that the Logic App does not know that we handle JSON data, instead it says something of application/octet-stream
, which is a binary data type.The Azure Function gets the following raw input:
The raw output of the Azure Function action looks like this.
And for reference the function stub of the Azure Function looks like this:
Convert into JSON data type
The documentation states, that Logic Apps can handle natively
application/json
and text/plain
(see Handle content types in logic apps). As we have already JSON data we can use the function @json()
to cast the data type to application/json
.Unfortunately, this approach cannot be saved by the Logic App Designer.
Error message
Save logic app failedFailed to save logic app logicapp. The template validation failed: ‘The template action ‘ProcessBlob2’ at line ‘1’ and column ‘43845’ is not valid: “The template language expression ‘json(@{body(‘Get_blob_content’)})’ is not valid: the string character ‘@’ at position ‘5’ is not expected.”.’.
Fortunately, this only a small shortcoming of the Azure Logic App Designer. We need to look at the configuration in code view. For that reason click on the tree dots
...
in the upper right corner of the Azure Function action and select Peek code
in the menu.We have to change the evaluation in the body property. It must not contain more than one expression wrapper
@()
. The documentation does not say explicitly how to nest expressions (see https://docs.microsoft.com/en-us/azure/logic-apps/logic-apps-workflow-definition-language#expressions), but after some trial and error, we know, we just need to remove the nested expression wrapper @{
and }
and leave everything else.Check again, if it’s working. Upload a new file.
We check the run history, again, and all actions did run successfully. Let’s check the raw input and output.
Raw input:
Raw output:
There is a difference in the input data of the Azure Function action, as there is no explicit content type, just pure JSON data.
Final Logic App
The final Logic App looks like this in the designer. Unfortunately, you don’t see all expressions. You need to peek inside the code, as seen in the step before.
To see everything switch to code view. That’s not nice to design, but it’s good enough to check our configuration.
Helpful Links
![Octet Octet](/uploads/1/2/6/6/126641320/880206569.jpg)
Azure Logic Apps
Azure Function Apps
- https://stackoverflow.com/questions/10399324/where-is-httpcontent-readasasync#=