wip: http response headers

Author: zach

examples/basic.zig

@@ -136,6 +136,12 @@ export fn http_get() i32 {
         return @as(i32, res.status);
     }
 
+    const headers = res.headers(allocator) catch unreachable;
+    const content_type = headers.get("content-type");
+    if (content_type) |t| {
+        plugin.log(.Debug, t);
+    }
+
     // get the bytes for the res body
     const body = res.body(allocator) catch unreachable;
     // => { "userId": 1, "id": 1, "title": "delectus aut autem", "completed": false }

src/ffi.zig

@@ -17,6 +17,7 @@ pub extern "extism:host/env" fn store_u64(ExtismPointer, u64) void;
 pub extern "extism:host/env" fn load_u64(ExtismPointer) u64;
 pub extern "extism:host/env" fn http_request(ExtismPointer, ExtismPointer) ExtismPointer;
 pub extern "extism:host/env" fn http_status_code() i32;
+pub extern "extism:host/env" fn http_headers() ExtismPointer;
 pub extern "extism:host/env" fn get_log_level() i32;
 pub extern "extism:host/env" fn log_trace(ExtismPointer) void;
 pub extern "extism:host/env" fn log_debug(ExtismPointer) void;

src/http.zig

@@ -4,6 +4,7 @@ const Memory = @import("Memory.zig");
 pub const HttpResponse = struct {
     memory: Memory,
     status: u16,
+    responseHeaders: Memory,
 
     /// IMPORTANT: it's the caller's responsibility to free the returned string
     pub fn body(self: HttpResponse, allocator: std.mem.Allocator) ![]u8 {
@@ -15,11 +16,19 @@ pub const HttpResponse = struct {
 
     pub fn deinit(self: HttpResponse) void {
         self.memory.free();
+        self.responseHeaders.free();
     }
 
     pub fn statusCode(self: HttpResponse) u16 {
         return self.status;
     }
+
+    pub fn headers(self: HttpResponse, allocator: std.mem.Allocator) !std.StringArrayHashMap([]u8) {
+        const buf = try allocator.alloc(u8, @intCast(self.responseHeaders.length));
+        self.responseHeaders.load(buf);
+        const out = try std.json.parseFromSlice(std.StringArrayHashMap([]u8), allocator, buf, .{ .allocate = .alloc_always, .ignore_unknown_fields = true });
+        return out.value;
+    }
 };
 
 pub const HttpRequest = struct {

src/main.zig

@@ -143,12 +143,14 @@ pub const Plugin = struct {
 
     pub fn logMemory(self: Plugin, level: LogLevel, memory: Memory) void {
         _ = self; // to make the interface consistent
+
         switch (level) {
             .Trace => extism.log_trace(memory.offset),
             .Debug => extism.log_debug(memory.offset),
             .Info => extism.log_info(memory.offset),
             .Warn => extism.log_warn(memory.offset),
             .Error => extism.log_error(memory.offset),
+            .Trace => unreachable, // TODO: trace
         }
     }
 
@@ -224,10 +226,15 @@ pub const Plugin = struct {
         const length = extism.length_unsafe(offset);
         const status: u16 = @intCast(extism.http_status_code());
 
+        const headersOffset = extism.http_headers();
+        const headersLength = extism.length(offset);
+        const headersMem = Memory.init(headersOffset, headersLength);
+
         const mem = Memory.init(offset, length);
         return http.HttpResponse{
             .memory = mem,
             .status = status,
+            .responseHeaders = headersMem,
         };
     }
 };