HTTPHeader

Read, set, and remove named HTTP headers via the Core library HTTPHeader helpers.

Runtime verified Differs from official docs Test scripts included

The HTTPHeader object provides Core-library helpers for header access in SSJS. Runtime testing shows GetValue reads the inbound request headers while SetValue/Remove operate on outbound headers — the two are separate collections, so you cannot read back a value you just set.

Requires Platform.Load("core", "1.1.5") before use.

Differs from official Salesforce docs

GetValue reads inbound headers only, so a header you set with SetValue comes back as null. Remove returns undefined, not "OK". Official docs also claim host cannot be changed; at runtime SetValue("Host", …) does emit an outbound Host header. content-length remains protected (the response keeps the real body length).

Show test script — inbound vs outbound and Remove

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Differs-from-docs: separate inbound/outbound collections + Remove undefined
 * + Host not protected (content-length is).
 *
 * Proves:
 *   1. DEV: GetValue after SetValue is null (official docs: one header bag).
 *   2. GetValue("Host") still returns the inbound CloudPage host string.
 *   3. DEV: Remove returns undefined (official docs: "OK").
 *   4. DEV: SetValue("Host", ...) succeeds (official docs: host cannot be changed).
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}

HTTPHeader.SetValue("X-Custom-Test", "hello");
var readBack = HTTPHeader.GetValue("X-Custom-Test");
assert("DEV GetValue after SetValue is null (official docs: shared collection)", readBack === null ? "null" : "other", "null");

var host = HTTPHeader.GetValue("Host");
assert("GetValue Host is a string", "" + (typeof host), "string");
assert("GetValue Host is non-empty", host && host.length > 0 ? "true" : "false", "true");

var removed = HTTPHeader.Remove("X-Custom-Test");
assert("DEV Remove returns undefined (official docs: OK)", removed === undefined ? "undefined" : "other", "undefined");
assert("DEV Remove typeof is undefined", "" + (typeof removed), "undefined");

var hostSet = HTTPHeader.SetValue("Host", "differs-host-probe");
assert("DEV SetValue Host succeeds (official docs: cannot change host)", hostSet === undefined ? "undefined" : "other", "undefined");
</script>

Methods

Method	Returns	Description
HTTPHeader.GetValue(name)	string | null	Returns the value of the named inbound request header (e.g. Host); returns null if absent — including for a header set via SetValue
HTTPHeader.SetValue(name, value)	void	Sets an outbound header value (content-length cannot be changed; host can)
HTTPHeader.Remove(headerName)	void	Removes a header entry; returns undefined

Show test script

<script runat="server">
/*
 * Chapter: Methods — Core load gate and HTTPHeader surface
 *
 * Proves:
 *   1. Before Platform.Load the bare name is undefined; invoking a method throws.
 *   2. After Platform.Load("core", "1.1.5") HTTPHeader is an object and
 *      GetValue / SetValue / Remove are functions.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function assertThrows(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = "" + ex.message; }
    Platform.Response.Write((threw ? "PASS " : "FAIL ") + id + " -> " + (threw ? "threw: " + msg : "did NOT throw") + "\n");
}
function typeOfThunk(fn) {
    try { return "" + fn(); } catch (ex) { return "THREW:" + ("" + ex.message); }
}

assert("before load typeof HTTPHeader is undefined", typeOfThunk(function () { return typeof HTTPHeader; }), "undefined");
assertThrows("before load HTTPHeader.GetValue throws", function () { return HTTPHeader.GetValue("Host"); });

Platform.Load("core", "1.1.5");
assert("after load typeof HTTPHeader is object", typeOfThunk(function () { return typeof HTTPHeader; }), "object");
assert("typeof HTTPHeader.GetValue is function", typeOfThunk(function () { return typeof HTTPHeader.GetValue; }), "function");
assert("typeof HTTPHeader.SetValue is function", typeOfThunk(function () { return typeof HTTPHeader.SetValue; }), "function");
assert("typeof HTTPHeader.Remove is function", typeOfThunk(function () { return typeof HTTPHeader.Remove; }), "function");
</script>

HTTPHeader.GetValue

Returns the value of the named inbound HTTP request header (e.g. Host). Returns null when the header is absent — including for a header you set earlier with SetValue, because GetValue and SetValue operate on separate (inbound vs outbound) collections.

Parameters

Name	Type	Required	Description
name	string	Yes	Name of the HTTP header to read

Examples

Platform.Load("core", "1.1.5");
var host = HTTPHeader.GetValue("Host");
Write(host);

Show test script

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Chapter: HTTPHeader.GetValue(name)
 *
 * Proves:
 *   1. GetValue("Host") returns a non-empty JavaScript string (inbound Host).
 *   2. Header names are case-insensitive (Host vs host).
 *   3. An absent inbound header returns strict null.
 *   4. DEV: GetValue after SetValue of the same custom name is still null
 *      (official docs imply one shared header collection).
 *
 * NON-ASSERTABLE: User-Agent presence — WebClient probes often omit it, so
 * absence is a client artefact, not proof the API cannot read it.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}

var host = HTTPHeader.GetValue("Host");
assert("GetValue Host typeof is string", "" + (typeof host), "string");
assert("GetValue Host is non-empty", host && host.length > 0 ? "true" : "false", "true");
assert("GetValue Host equals lowercase host", HTTPHeader.GetValue("host") === host ? "true" : "false", "true");

var absent = HTTPHeader.GetValue("X-Absent-HttpHeader-Ts");
assert("absent header is strict null", absent === null ? "null" : "other", "null");
assert("absent header is falsy", absent ? "truthy" : "falsy", "falsy");

HTTPHeader.SetValue("X-GetValue-Readback", "should-not-read");
var readBack = HTTPHeader.GetValue("X-GetValue-Readback");
assert("DEV GetValue after SetValue is null (official docs: shared collection)", readBack === null ? "null" : "other", "null");
</script>

HTTPHeader.SetValue

Sets the value of the named outbound HTTP header. The content-length header cannot be changed (the response keeps the real body length). Official docs also claim host is protected, but SetValue("Host", …) does emit an outbound Host header. Values set here are not readable via GetValue, which reads inbound headers.

Parameters

Name	Type	Required	Description
name	string	Yes	Name of the header to set
value	string | number | boolean	Yes	Value to assign to the header

A boolean value is accepted, but the outbound header uses CLR capitalization (True / False), not lowercase true / false. Prefer an explicit string when the exact token matters. See known bugs.

Examples

Platform.Load("core", "1.1.5");
HTTPHeader.SetValue("X-Custom-Header", "example");

Show test script

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Chapter: HTTPHeader.SetValue(name, value)
 *
 * Proves:
 *   1. SetValue returns undefined (void-like; typeof "undefined").
 *   2. A string value call does not throw.
 *   3. TYPE-ACCEPTANCE: number value is Accepted (call succeeds).
 *   4. TYPE-ACCEPTANCE: boolean value is Accepted (call succeeds) —
 *      BUG: raw ResponseHeaders show CLR "True"/"False" (not lowercase).
 *   5. DEV: SetValue("Host", ...) does not throw (official docs: host
 *      cannot be changed). Outbound Host emission is NON-ASSERTABLE here.
 *   6. SetValue("content-length", ...) does not throw; protection of the
 *      real Content-Length is NON-ASSERTABLE in the body (raw headers).
 *
 * NON-ASSERTABLE in body: exact outbound header strings for custom / Host /
 * Content-Length / boolean CLR capitalization — prove via ResponseHeaders.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function assertThrows(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = "" + ex.message; }
    Platform.Response.Write((threw ? "PASS " : "FAIL ") + id + " -> " + (threw ? "threw: " + msg : "did NOT throw") + "\n");
}

var retStr = HTTPHeader.SetValue("X-SetValue-Str", "example");
assert("SetValue string returns undefined", retStr === undefined ? "undefined" : "other", "undefined");
assert("SetValue string typeof is undefined", "" + (typeof retStr), "undefined");

var retNum = HTTPHeader.SetValue("X-SetValue-Num", 42);
assert("number value SetValue returns undefined", retNum === undefined ? "undefined" : "other", "undefined");

var retTrue = HTTPHeader.SetValue("X-SetValue-BoolT", true);
var retFalse = HTTPHeader.SetValue("X-SetValue-BoolF", false);
assert("BUG boolean true SetValue accepted (outbound CLR True)", retTrue === undefined ? "undefined" : "other", "undefined");
assert("BUG boolean false SetValue accepted (outbound CLR False)", retFalse === undefined ? "undefined" : "other", "undefined");

var retHost = HTTPHeader.SetValue("Host", "ssjs-guide-host-probe");
assert("DEV SetValue Host does not throw (official docs: cannot change host)", retHost === undefined ? "undefined" : "other", "undefined");

var retCL = HTTPHeader.SetValue("content-length", "1");
assert("SetValue content-length does not throw", retCL === undefined ? "undefined" : "other", "undefined");

var afterSet = HTTPHeader.GetValue("X-SetValue-Str");
assert("GetValue still null after SetValue string", afterSet === null ? "null" : "other", "null");
</script>

HTTPHeader.Remove

Removes the named entry from the HTTP header. Returns undefined — call it for its side effect only.

Parameters

Name	Type	Required	Description
headerName	string	Yes	Name of the header to remove

Examples

Platform.Load("core", "1.1.5");
HTTPHeader.Remove("X-Custom-Header"); // no useful return value

Show test script

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Chapter: HTTPHeader.Remove(headerName)
 *
 * Proves:
 *   1. DEV: Remove returns undefined, not the "OK" string official docs claim.
 *   2. Remove on a just-set custom name and on an never-set name both return undefined.
 *
 * NON-ASSERTABLE in body: that the outbound header is absent after Remove —
 * prove via raw ResponseHeaders (X-Keep present after Set, absent after Remove).
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}

HTTPHeader.SetValue("X-Remove-Probe", "temp");
var removed = HTTPHeader.Remove("X-Remove-Probe");
assert("DEV Remove returns undefined (official docs: OK)", removed === undefined ? "undefined" : "other", "undefined");
assert("DEV Remove typeof is undefined (official docs: OK)", "" + (typeof removed), "undefined");

var removedAbsent = HTTPHeader.Remove("X-Remove-Never-Set");
assert("Remove absent name returns undefined", removedAbsent === undefined ? "undefined" : "other", "undefined");
</script>

See Also

• Platform.Request — incoming request data
• Platform.Response — response helpers (cookies, redirect, content type)