multipart: add body reading

src/main.zig

@@ -58,6 +58,7 @@ const ContentDisposition = struct {
 const Part = struct {
     disposition: ContentDisposition,
     content_type: []const u8,
+    body: []const u8,
 };
 
 const Multipart = struct {
@@ -170,9 +171,25 @@ const Multipart = struct {
             }
         }
 
+        // the rest of the reader until we find a matching boundary is the part body.
+        // hzzp does not do it for us because it cant find a body encoding
+        // (content-length, content-encoding)
+        //
+        // we can use the fact that we know the reader is FixedBufferStream
+        // to extract the remaining body, then trim the boundary!
+        //
+        // THIS ASSUMES ONLY ONE FILE IS IN THE WIRE.
+
+        const remaining_body = self.stream.buffer[self.stream.pos..self.stream.buffer.len];
+
+        var end_boundary_buf: [512]u8 = undefined;
+        const boundary_end_marker = try std.fmt.bufPrint(&end_boundary_buf, "{s}--\r\n", .{self.boundary});
+        const actual_body = std.mem.trim(u8, remaining_body, boundary_end_marker);
+
         return Part{
             .disposition = content_disposition.?,
             .content_type = content_type.?,
+            .body = actual_body,
         };
     }
 };