PowerShell调用丹麦StatBank API遇REQUEST-EMPTY错误求助

错误信息 #

Error calling the API: "errorTypeCode":"REQUEST-EMPTY","message":"Supply valid JSON-object when posting.".Exception.Message"

问题背景 #

调用丹麦StatBank API时出现上述错误，第一个脚本可正常运行，第二个脚本执行失败，无法定位语法差异。

正常运行的脚本 #

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$apiUrl = "https://api.statbank.dk/v1/data"

$payload = @{
    "table" = "FOLK1c"
    "format" = "CSV"
    "variables" = @(
        @{
            "code" = "IELAND"
            "values" = @("5100","0000")
        }
    )
}

try {
       $response = Invoke-RestMethod -Uri $apiUrl -Headers @{ "Content-Type" = "application/json" } -Method Post -Body ($payload | ConvertTo-Json)

       if ($response) {
        # Store CSV data in a variable
        $csvData = $response

        
        $filePath = "C:\"

       
        $csvData | Out-File -FilePath $filePath -Encoding UTF8

        Write-Host "CSV data has been saved to: $filePath"
    } else {
        Write-Host "API returned no data."
    }
}
catch {
    Write-Host "Error calling the API: $_.Exception.Message"
}

运行失败的脚本 #

\[Net.ServicePointManager\]::SecurityProtocol = \[Net.SecurityProtocolType\]::Tls12

$apiUrl = "https://api.statbank.dk/v1/data"

$payload = @{
"table" = "AUS08"
"format" = "CSV"
"variables" = @(
@{
"code" = "OMRÅDE"
"values" = @("*")
},
@{
"code" = "SAESONFAK"
"values" = @("*")
},
@{
"code" = "Tid"
"values" = @("\*")
}
)
} | ConvertTo-Json

try {
$response = Invoke-WebRequest -Uri $apiUrl -Headers @{ "Content-Type" = "application/json" } -Method Post -Body $payload

       if ($response) {
        
        $csvData = $response.Content
    
        
        $filePath = "C:\"
    
       
        $csvData | Out-File -FilePath $filePath -Encoding UTF8
    
        Write-Host "CSV data has been saved to: $filePath"
    } else {
        Write-Host "API returned no data."
    }

}
catch {
Write-Host "Error calling the API: $\_.Exception.Message"
} 

错误原因分析 #

失败脚本存在3处不必要的反斜杠转义，导致代码解析异常：

• \[Net.ServicePointManager\]和\[Net.SecurityProtocolType\]中的反斜杠，会让PowerShell无法识别这些.NET类型，后续逻辑执行异常。
• values数组中的@("\*")多了反斜杠，星号被转义成普通字符，既不符合API对通配符的要求，也会导致JSON格式错误。
• 异常捕获中的$\_.Exception.Message多了反斜杠，无法正确获取异常信息。

这些问题最终导致发送给API的JSON不符合要求，触发"REQUEST-EMPTY"错误。

修复后的脚本 #

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$apiUrl = "https://api.statbank.dk/v1/data"

$payload = @{
    "table" = "AUS08"
    "format" = "CSV"
    "variables" = @(
        @{
            "code" = "OMRÅDE"
            "values" = @("*")
        },
        @{
            "code" = "SAESONFAK"
            "values" = @("*")
        },
        @{
            "code" = "Tid"
            "values" = @("*")
        }
    )
} | ConvertTo-Json

try {
    $response = Invoke-WebRequest -Uri $apiUrl -Headers @{ "Content-Type" = "application/json" } -Method Post -Body $payload

    if ($response) {
        $csvData = $response.Content
        $filePath = "C:\"
        $csvData | Out-File -FilePath $filePath -Encoding UTF8
        Write-Host "CSV data has been saved to: $filePath"
    } else {
        Write-Host "API returned no data."
    }
}
catch {
    Write-Host "Error calling the API: $_.Exception.Message"
} 

内容的提问来源于stack exchange，提问作者Staffyeahh