(PowerBuilder) curl with Variable Substitution in a GraphQL Request Body

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This example shows how to use variables inside a graphql request body using the {{variable_name}} syntax. When the HTTP request’s Content-Type indicates graphql, Chilkat automatically applies proper escaping to each substituted value, ensuring the resulting graphql remains valid.

Note: This example requires Chilkat v11.5.0 or greater.

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integer li_rc
integer li_Success
oleobject loo_SbCurl
oleobject loo_Curl
oleobject loo_SbRawRequest

li_Success = 0

li_Success = 0

// Variable names are enclosed between {{ and }}
// Important: Variables should be placed inside the quotes.

// curl -X POST https://api.example.com/graphql \
//   -H "Content-Type: application/graphql; charset=utf-8" \
//   -H "Accept: application/json" \
//   --data-binary "mutation {
//   createUser(
//     input: {
//       name: \"{{name}}\"
//       city: \"{{city}}\"
//       note: \"{{note}}\"
//       bio: \"{{bio}}\"
//     }
//   ) {
//     id
//     name
//   }
// }"

// Build the above curl command.
loo_SbCurl = create oleobject
li_rc = loo_SbCurl.ConnectToNewObject("Chilkat.StringBuilder")
if li_rc < 0 then
    destroy loo_SbCurl
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_SbCurl.AppendLn("curl -X POST https://api.example.com/graphql ~")
loo_SbCurl.AppendLn("  -H ~"Content-Type: application/graphql; charset=utf-8~" ~")
loo_SbCurl.AppendLn("  -H ~"Accept: application/json~" ~")
loo_SbCurl.AppendLn("  -d ~"mutation {")
loo_SbCurl.AppendLn("  createUser(")
loo_SbCurl.AppendLn("    input: {")
loo_SbCurl.AppendLn("      name: \~"{{name}}\~"")
loo_SbCurl.AppendLn("      city: \~"{{city}}\~"")
loo_SbCurl.AppendLn("      note: \~"{{note}}\~"")
loo_SbCurl.AppendLn("      bio: \~"{{bio}}\~"")
loo_SbCurl.AppendLn("    }")
loo_SbCurl.AppendLn("  ) {")
loo_SbCurl.AppendLn("    id")
loo_SbCurl.AppendLn("    name")
loo_SbCurl.AppendLn("  }")
loo_SbCurl.AppendLn("}~"")

loo_Curl = create oleobject
li_rc = loo_Curl.ConnectToNewObject("Chilkat.HttpCurl")

// Provide values for variables
loo_Curl.SetVar("name","José O'Connor")
loo_Curl.SetVar("city","München")
loo_Curl.SetVar("note","He said ~"Hello, world!~" — and left…")
loo_Curl.SetVar("bio","Loves sushi, café visits, and π ≈ 3.14159")

// To demonstrate how the variables are replaced, this example does not execute the curl command. 
// Instead, it generates the raw HTTP request that would be sent if the curl command were run.
loo_SbRawRequest = create oleobject
li_rc = loo_SbRawRequest.ConnectToNewObject("Chilkat.StringBuilder")

li_Success = loo_Curl.ToRawRequest(loo_SbCurl.GetAsString(),loo_SbRawRequest)
if li_Success = 0 then
    Write-Debug loo_Curl.LastErrorText
    destroy loo_SbCurl
    destroy loo_Curl
    destroy loo_SbRawRequest
    return
end if

Write-Debug loo_SbRawRequest.GetAsString()

// The output is shown below.
// Notice the quote chars around "Hello, world!" are properly escaped.

// POST /graphql HTTP/1.1
// Accept: application/json
// Host: api.example.com
// Content-Type: application/graphql; charset=utf-8
// Content-Length: 250
// 
// mutation {
//   createUser(
//     input: {
//       name: "José O'Connor"
//       city: "München"
//       note: "He said \"Hello, world!\" — and left…"
//       bio: "Loves sushi, café visits, and π ≈ 3.14159"
//     }
//   ) {
//     id
//     name
//   }
// }


destroy loo_SbCurl
destroy loo_Curl
destroy loo_SbRawRequest