Sending a complex html as the body of email from the command line via an SendGrid API-CodePudding

I need to send an HTML file as the body of an eamil to several customers. Our company will be using SendGrid for this, and I need to be able to send the email via API Curl Call.

The way that I'm doing it so far works for simple html or plain text:

curl -s --request POST \
--url https://api.sendgrid.com/v3/mail/send \
--header "Authorization: Bearer SECRET_API_KEY" \
--header 'Content-Type: application/json' \
--data '{"personalizations":[{"to":[{"email":"[email protected]"},{"email":"[email protected]"}]}],"from":{"email":"[email protected]"},"subject":"Testing sending emails via SendgridAPI","content":[{"type":"text\/html","value":"Test API Email From ME"}]}'

Now this works just fine. The problem is when I want to replace 'Test API Email From ME' with the contents of a rather large, complex HTML file. This has all the usual cli nightmares such as a mix of ' and " and new lines everywhere. I need to sanatize the HTML in order to accomplish three things:

The final result needs to be a valid command line string
The --data switch argument needs to remain a valid JSON enconded string
The HTML should not break.

What I do is I create the actual string command and the execute it using a scripting language. So I can perform any operation that I want on the html before inserting it in the value field of the content field. So my question is: what are the string operations that I should perform on the html so that I can send the email using this methodology?

CodePudding user response：

Using `jq` and bash

I'll do it with static data, you may improve upon it

Define a JSON template for the API:

IFS='' read -r -d '' json_template <<'EOF'
{
  "personalizations": [
    {
      "to": [
        { "email": "[email protected]" },
        { "email": "[email protected]" }
      ]
    }
  ],
  "from": { "email": "[email protected]" },
  "subject": "Testing sending emails via SendgridAPI",
  "content": [
    {
      "type": "text/html",
      "value": "Test API Email From ME"
    }
  ]
}
EOF

Define the HTML content:

IFS='' read -r -d '' html_email <<'EOF'
<!doctype html>
<html>
  <head>
    title>Simple Email</title>
  </head>
  <body>
    Test API Email From ME
  </body
</html>
EOF

Replace the email content in the JSON with the HTML

json_data=$(
    jq -c -n \
        --arg html "$html_email" \
        --argjson template "$json_template" \
        '$template | .content[0].value = $html'
)

Send the query

curl -s --request POST \
    --url https://api.sendgrid.com/v3/mail/send \
    --header "Authorization: Bearer SECRET_API_KEY" \
    --header 'Content-Type: application/json' \
    --data "$json_data"

CodePudding user response：

Here is how you can compose a proper JSON data payload with jq so it can be sent to the API.

jq will ensure every values, recipients, from, subject and the html body will be respectively encoded to proper JSON data objects, arrays and strings before it is submitted as --data @- to curl:

I added comments everywhere, so it is very clear what is done at every step:

#!/usr/bin/env bash

recipients=(
  '[email protected]'
  '[email protected]'
)

from='[email protected]'
subject='Testing sending emails via SendgridAPI'

# Streams null-delimited recipients array entries
printf '%s\0' "${recipients[@]}" |

# jq slurps the null-delimited recipients,
# read the raw html content into the jq $contentHTML variable
# and integrate it all as a proper JSON
jq --slurp --raw-input --rawfile contentHTML example.html \
  --arg from "$from" \
  --arg subject "$subject" \
'
# Fills the jq $recipient JSON array variable
# by splitting the null-delmited entries
# from the incoming stream
split( "\u0000") as $recipients | 

{
  "personalizations": [
    {
      # Uses the $recipients array that has been
      # slurped  from the input stream
      "to": $recipients
    }
  ],
  "from": {

    # Use the $from that has been passed as --arg
    "email": $from
  },

  # Use the $subject that has been passed as --arg
  "subject": $subject,

  "content": [
    {
      "type": "text/html",
      "value": $contentHTML
    }
  ]
}
' |

# Get the resultant JSON piped into curl
# that will read the data from the standard input
# using --data @-
# rather than passing it as an argument, because
# the payload could exceed the maximum length of arguments
curl -s --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header "Authorization: Bearer SECRET_API_KEY" \
  --header 'Content-Type: application/json' \
  --data @-

Using jq and bash

Using `jq` and bash