Classic ASP Requires Chilkat v11.7.0+
Box: Find a File by Name Across All Folder Pages

Run the reusable setup once per HttpCurl object, then select names and execute the operation. The setup is repeated here only to make this published example independently runnable. Find one exact, case-sensitive filename in a parent folder selected by name, checking the item type and every page before using its ID.
See the Box API guide for setup and the complete workflow.
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<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<body>
<%
success = 0

'  Requires Chilkat 11.7.0 or later and a previously unlocked Chilkat bundle.
'  See Global Unlock Sample.
'  Guide: Box API Guide.

success = 0

'  BEGIN ONE-TIME SETUP
'  This block is repeated so each published example can run on its own.
'  In an application, run the setup example once and pass the SAME curl object
'  to operation code below. Do not recreate it for every operation.
'  See Reusable Box HttpCurl Setup.
set curl = Server.CreateObject("Chilkat.HttpCurl")
curl.SetVar "access_token","BOX_ACCESS_TOKEN"
curl.SetVar "parent_name","/"
'  Box's fixed root ID is an implementation detail; callers supply names.
curl.SetVar "parent_id","0"
set setupCommand = Server.CreateObject("Chilkat.StringBuilder")

'  Register findParent; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/folders/0/items?limit=1000&fields=id,type,name"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("findParent",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register findFolder; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/folders/{{parent_id}}/items?limit=1000&fields=id,type,name"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("findFolder",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register findFile; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/folders/{{folder_id}}/items?limit=1000&fields=id,type,name"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("findFile",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register findDestination; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/folders/0/items?limit=1000&fields=id,type,name"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("findDestination",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register getFileDetails; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/files/{{file_id}}?fields=id,sha1,file_version"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("getFileDetails",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register getEnterprise; registration sends no request.
success = setupCommand.SetString("curl -X GET ""https://api.box.com/2.0/users/me?fields=enterprise"" -H ""Authorization: Bearer ACCESS_TOKEN""")
setupReplacements = setupCommand.Replace("ACCESS_TOKEN",curl.GetVar("access_token"))
success = curl.AddFunction("getEnterprise",setupCommand.GetAsString())
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  Register output rules once. Chilkat 11.7.0 evaluates {{name}} variables
'  when extracting each output, using the current value at that time.
success = curl.AddOutput2("findParent","entries","name","{{parent_name}}",1,"id","parent_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput2("findFolder","entries","name","{{folder_name}}",1,"id","folder_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput2("findFile","entries","name","{{file_name}}",1,"id","file_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput2("findDestination","entries","name","{{destination_name}}",1,"id","destination_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput("getFileDetails","file_version.id","file_version_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput("getFileDetails","sha1","file_sha1")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

success = curl.AddOutput("getEnterprise","enterprise.id","enterprise_id")
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
    Response.End
End If

'  END ONE-TIME SETUP
'  The name lookups below assume each listing fits in one page (1000 items).
'  Parent and destination names select root children; folder_name selects a child
'  of parent_name. "/" selects the root parent. These are not arbitrary paths.

'  BEGIN OPERATION -- keep the configured object when reusing it.
'  Inputs are names. Retain cached IDs when the selected names have not changed.
parentName = "/"
folderName = "images"
If ((curl.GetVar("parent_name") <> parentName) Or ((parentName = "/") And (curl.VarDefined("parent_id") = 0))) Then
    curl.SetVar "parent_name",parentName
    curl.ClearVar "parent_id"
    curl.ClearVar "folder_id"
    curl.ClearVar "file_id"
    curl.ClearVar "file_version_id"
    curl.ClearVar "file_sha1"
    If (parentName = "/") Then
        curl.SetVar "parent_id","0"
    End If

End If

If (curl.GetVar("folder_name") <> folderName) Then
    curl.SetVar "folder_name",folderName
    curl.ClearVar "folder_id"
    curl.ClearVar "file_id"
    curl.ClearVar "file_version_id"
    curl.ClearVar "file_sha1"
End If

curl.SetVar "marker",""
set page = Server.CreateObject("Chilkat.JsonObject")
i = 0
count = 0
more = 1

set authorizedCommand1 = Server.CreateObject("Chilkat.StringBuilder")
success = authorizedCommand1.SetString("curl -X GET ""https://api.box.com/2.0/folders/{{folder_id}}/items?usemarker=true&limit=1000&fields=id,type,name"" -H ""Authorization: Bearer {{access_token}}""")
headerReplacement1 = authorizedCommand1.Replace("{{access_token}}",curl.GetVar("access_token"))
pageCommand = authorizedCommand1.GetAsString()
wantedName = "penguins.jpg"
fileId = ""
matches = 0
Do While (more = 1)
    curl.ClearTargetOutput "*"
    success = curl.DoYourThing(pageCommand)
    If ((success <> 1) Or (curl.StatusCode <> 200)) Then
        Response.Write "<pre>" & Server.HTMLEncode( "Box request failed. HTTP status: " & curl.StatusCode) & "</pre>"
        Response.Write "<pre>" & Server.HTMLEncode( "Failure reason: " & curl.FailReason) & "</pre>"
        Response.Write "<pre>" & Server.HTMLEncode( curl.ResponseBodyStr) & "</pre>"
        Response.End
    End If

    success = curl.GetResponseJson(page)
    If (success <> 1) Then
        Response.Write "<pre>" & Server.HTMLEncode( curl.LastErrorText) & "</pre>"
        Response.End
    End If

    count = page.SizeOfArray("entries")
    i = 0
    Do While i < count
        page.I = i
        If ((page.StringOf("entries[i].type") = "file") And (page.StringOf("entries[i].name") = wantedName)) Then
            fileId = page.StringOf("entries[i].id")
            matches = matches + 1
        End If

        i = i + 1
    Loop
    more = 0
    If (page.HasMember("next_marker") = 1) Then
        If (page.IsNullOf("next_marker") = 0) Then
            nextMarker = page.StringOf("next_marker")
            If (nextMarker <> "") Then
                If (nextMarker = curl.GetVar("marker")) Then
                    Response.Write "<pre>" & Server.HTMLEncode( "Box returned the same pagination marker; stopping.") & "</pre>"
                    Response.End
                End If

                curl.SetVar "marker",nextMarker
                set authorizedCommand2 = Server.CreateObject("Chilkat.StringBuilder")
                success = authorizedCommand2.SetString("curl -X GET ""https://api.box.com/2.0/folders/{{folder_id}}/items?usemarker=true&limit=1000&fields=id,type,name&marker={{marker}}"" -H ""Authorization: Bearer {{access_token}}""")
                headerReplacement2 = authorizedCommand2.Replace("{{access_token}}",curl.GetVar("access_token"))
                pageCommand = authorizedCommand2.GetAsString()
                more = 1
            End If

        End If

    End If

Loop
If (matches <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Expected exactly one matching file. Matches: " & matches) & "</pre>"
    Response.End
End If

curl.SetVar "file_id",fileId
Response.Write "<pre>" & Server.HTMLEncode( "File ID: " & fileId) & "</pre>"
curl.ClearTargetOutput "*"
set authorizedCommand3 = Server.CreateObject("Chilkat.StringBuilder")
success = authorizedCommand3.SetString("curl -X GET ""https://api.box.com/2.0/files/{{file_id}}?fields=id,type,name,parent,size"" -H ""Authorization: Bearer {{access_token}}""")
headerReplacement3 = authorizedCommand3.Replace("{{access_token}}",curl.GetVar("access_token"))
success = curl.DoYourThing(authorizedCommand3.GetAsString())
If ((success <> 1) Or (curl.StatusCode <> 200)) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Box request failed. HTTP status: " & curl.StatusCode) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "Failure reason: " & curl.FailReason) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( curl.ResponseBodyStr) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( curl.ResponseBodyStr) & "</pre>"

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