Download attachment using SNOW REST API attachment table

[Naresh Kumar Gn]

Hi All,

I am trying to download an attachment which is there on a SNOW incident where I was able to download the incident but I am unable to open the downloaded file which I got via API. But when I download the same file using GUI I can open it.

Url I tried to used to download the file is given below,

https://<SNOWInstanceURL>/api/now/attachment?sysparm_query=table_name%3Dincident%5Etable_sys_id%3D<IncidentSysId>

Sample Script"

$IncidentNumber = "Incident#"
$admin = "admin"
$password = "admin" | ConvertTo-SecureString -AsPlainText -Force 
$Credential = New-Object pscredential -ArgumentList ($admin,$password)
$Uri = "https://devxxxxx.service-now.com/api/now/table/incident?sysparm_query=number=$($IncidentNumber)&sysparm_fields=sys_id&sysparm_limit=1"
$IncidentResult = Invoke-RestMethod -Uri $Uri -Method Get -Credential $Credential
if($IncidentResult.result.sys_id -ne $null) {
    $IncidentAttachments = Invoke-RestMethod -Uri "https://devxxxxx.service-now.com/api/now/attachment?sysparm_query=table_sys_id=$($IncidentResult.result.sys_id)" -Method Get -Credential $Credential
    $Results = $IncidentAttachments.result | Select file_name , download_link
    foreach($Result in $Results) {
        Invoke-RestMethod -Uri $($Result.download_link) -Method Get -Credential $Credential -OutFile C:\Temp\Demo\$($Result.file_name)
    }
}
else{
    "Incident Not Found!"
}

Regards,

Naresh

[rahulpandey]

Hi, To get the attachment file, you need to use below endpoint Instance url/api/now/attachment//file Please refer below document https://docs.servicenow.com/bundle/geneva-servicenow-platform/page/integrate/inbound_rest/reference/r_AttachmentAPI-GETidFile.html

[Naresh Kumar Gn · Accepted solution]

Yes, I have gone through the link but in my organization, they have added an encryption mechanism and they have blocked the download if it was not triggered internally within the snow.

[Nikita9]

Hi Naresh,

Can you please explain how you are able to download attachment file using this code? I am also having a requirement where i need to download all RITMs attachments if user clicks on an API. 

Pls help.

Regards,

Nikita

[Naresh Kumar G1]

Use this code to download all attachment from a RITM

param (
    $RITM,

    $DownloadLocation,

    $snowurl,

    $fileextenstion,
   
    $snowUser,

    $snowPass,

    $IdAMUser,

    $IdAMPass,

    $APIKey,

    $ApiSecret

)
begin {
    if (-not ([System.Management.Automation.PSTypeName]'TrustAllCertsPolicy').Type) {
        Add-Type -TypeDefinition @"
            using System.Net;
            using System.Security.Cryptography.X509Certificates;
            public class TrustAllCertsPolicy : ICertificatePolicy {
                public bool CheckValidationResult(
                    ServicePoint srvPoint, X509Certificate certificate,
                    WebRequest request, int certificateProblem) {
                    return true;
                }
            }
"@ 
    }

}

process {
    [System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy -ErrorAction SilentlyContinue
    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

    $Authorization = [Convert]::ToBase64String(
        [Text.Encoding]::ASCII.GetBytes(
            (
                "{0}:{1}" -f $snowUser , $snowPass
            )
        )
    )
    $ProxyAuthorization = [Convert]::ToBase64String(
        [Text.Encoding]::ASCII.GetBytes(
            (
                "{0}:{1}" -f $IdAMUser , $IdAMPass
            )
        )
    )
    $Headers = @{
        apikey                = $APIKey
        apikeySecret          = $ApiSecret
        "proxy-authorization" = "basic " + $ProxyAuthorization
        authorization         = "basic " + $Authorization
        "Content-Type"        = "application/json"
    }

    try {
        $TempDownloadLocation = $DownloadLocation# + "\" + $RITM
        $PathCheck = Test-Path -Path $TempDownloadLocation
        if ($PathCheck) { }
        else {
            $Tempresult1 = New-Item -ItemType Directory -Force -Path $TempDownloadLocation
        }
        $AttachmentResult = "NotFound"

        $RetrieveTableSysIdUri = $snowurl + "/api/now/table/sc_req_item?sysparm_query=number%3D$($RITM)&sysparm_limit=1"
        $RetrieveTableSysIdQuery = Invoke-RestMethod -Method Get -Uri $RetrieveTableSysIdUri -Headers $Headers
        $TableSysId = $RetrieveTableSysIdQuery.result.sys_id

        $RetrieveAttachmentLinkUri = $snowurl + "/api/now/attachment?sysparm_query=table_name%3Dsc_req_item%5Etable_sys_id%3D$($TableSysId)"
        $RetrieveAttachmentQuery = Invoke-RestMethod -Method Get -Uri $RetrieveAttachmentLinkUri -Headers $Headers
        $RetrieveAttachment = $RetrieveAttachmentQuery.result.download_link
$EachAttachment = $RetrieveAttachmentQuery.result[0]
            $RetrieveAttachment = $EachAttachment.download_link
            $EachAttachmentFileName = $EachAttachment.file_name
            $Split = ($EachAttachmentFileName -split '\.')
            if ($Split[1] -imatch $fileextenstion) {
                $FileName = $Split[0] + "_" + $RITM + "." + $Split[1];
                Invoke-RestMethod -Method Get -Uri $RetrieveAttachment -Headers $Headers -OutFile "$TempDownloadLocation\$($FileName)"
                $resultJson = [PSCustomObject]@{
                    FileName = $FileName
                    Result = "Found"
                } | ConvertTo-Json
                
            }
            if($resultJson.count -gt 0){
            
            $resultJson}else{
            "CSV not Found"
            }

    }
    catch {
        [PSCustomObject]@{
            FileName = $FileName
            Result = $_.Exception
        } | ConvertTo-Json
    }
}
end {
}