You can use the Amazon S3 connector to read files from S3 and create files on S3.

Please note that S3 does not support updating existing files, so if you want to append data, you typically create a new file with the old data plus the new data to append.

Below, we'll use a simple Data Blend to create a file in a bucket on Amazon S3, either using JSON format or CSV file format (comma separated values).

Create a CSV file

Example Data Blend:

In the above example, we are using a variable called "row" of type "Object", to create all columns of one CSV row. While the variable is an object, it will automatically be converted to a CSV line, based on the file name extension of the S3 file (see below).

First we make the variable "row" empty. Next, we add a key/value for each column. We're using keys "column1", "column2" etc. but the keys are not used in the CSV file, only the values are used.

After the variable is created, we use the block "Add line to S3 file" to add individual lines to an S3 file. The above variable is used as "Data" input for the block "Add line to S3 file":

The extension of the filename will determine the file format, so make sure to use a filename with extension ".csv".

Note: if the file already exists, it will be overwritten on each run of the Data Blend, S3 does not support updating an existing file.

Make sure to add the S3 block "Complete file" at the end of the Data Blend to close the file on S3.

A word about using variables to create CSV files

You do not have to use a variable in your Data Blend to create a CSV file. Instead, you could reference output from another block directly in the "Data" field of the block "Add line to S3 file". Example:

In this example, one column will be created in the CSV file, for each property of the Item from "Hubspot list contacts", so the CSV file will contain "name", "email" etc. However, in this example you have no control over which data is written to which column. That's why we use a variable above to have control over which columns are added.

Create a JSON file

Similar to the above example, you can also create a JSON file on S3, simply by using a filename with extension ".json" in the block "Add line to S3 file".

Please note that will automatically create an array in the JSON file, and the block "Add line to S3 file" will add items to this array.

The block "Complete file" at the end will make sure the array is terminated correctly in the file.

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