Request Ethereum API: Using variables in parameters
As an Ethereum Developer, You Are Probable Familiar with the Importance of Using the Correct Parameters Names And Data Types in Your Requirements. However, one usual question arises when working with variables that need to be passed as parameters. In this article, we will explore why api rejects your variable {{{{{{Sellprice}} and provide a solution.
Error “signature for this request is not valid”
When submitting API requests in the postman or any other tool, you will be bbliged to determine the name of the parameter (without allegation), followed by a type of data ({{{{{{{{Sellprice}}}}} ). The Exact Syntax May Vary Depending on the End Point of the API and its specific requirements. However, the usual question arises when variables are used without quotes.
Problem with {{}} syntax
In JavaScript, Literals Template ({…} ) and string interpolation ( $ {…} ) have different behavioral behavior when it comes to variables. When using{{}}}}, the postman interprets{} As the beginning of the name, which can lead to a Problem if the variable contains special signs or spaces.
For Example, Consider A Request with this parameter:
`Json
Post/API/Price HTTP/1.1
Content Type: App/JSON
{
"Price": "{Sellprice}}",
"Symbol": "{{Symbol}"
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If you use {}}} Syntax to Pass the Sellprice Variable, The Postman Will Recognize It As A Template Literally and Neglect It In The Body of the Request.
Why {}} is not Valid
To solve this problem, you have to escape the signs of {} around your variable using double curly snacks (‘{{{{{}}} ). This tells the postman that the following Parts of the Holder of the Place for Values Are:
Json
Post/API/Price HTTP/1.1
Content Type: App/JSON
{
"Price": "{Sellprice}}",
"Symbol": "{{Symbol}"
Iche
Solution
To use your variable {sellprice}}}} in request, follow thesis steps:
- Avoid
{{}Around Your Variable Using Double Curly Carriers ({{{{{{{{}}}).
- Keep the rest of the syntax intact.
- In The Body of the Postman Request, Replace{}}
{{{{{{{{}}}>.
Here’s an updated example:
`Json
Post/API/Price HTTP/1.1
Content Type: App/JSON
{
"Price": "{Sellprice}}",
"Symbol": "{{Symbol}"
Iche
Tips and variations
- If you use an engine with a template (like a steering wheel or a mustache), you will need to use
{{{{{Variable_name}}Syntax Instead or ‘{}.
- In some cases, you may need to use individual quotes (
) around your name of the variable if it contains special characters. For Example:
Json
Post/API/Price HTTP/1.1
Content Type: App/JSON
{
"Price": "" {{Sellprice}} ",
"Symbol": "" {{Symbol}} ""
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Following these steps, you should be able to successful use variable {sellprice}}} in the parameters of API.
Conclusion
Using variables with special signs or spaces can lead to errors when sending a postman request. Avoiding {{} Around your variable using double curly brackets ({{{{{{{{{}}}> `')'')'‘)’‘)’ postman interprets and transmits your values as needed.
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