refactor: use a default contentType of application/json in Forms

packages/binding-coap/src/coap-client.ts

@@ -159,7 +159,7 @@ export default class CoapClient implements ProtocolClient {
                 debug(`CoapClient received Content-Format: ${res.headers["Content-Format"]}`);
 
                 // FIXME does not work with blockwise because of node-coap
-                const contentType = res.headers["Content-Format"] ?? form.contentType ?? ContentSerdes.DEFAULT;
+                const contentType = res.headers["Content-Format"] ?? form.contentType;
 
                 res.on("data", (data: Buffer) => {
                     next(new Content(`${contentType}`, Readable.from(res.payload)));
@@ -253,7 +253,7 @@ export default class CoapClient implements ProtocolClient {
         const method = form["cov:method"] ?? defaultMethod;
         debug(`CoapClient got Form "method" ${method}`);
 
-        const contentFormat = form["cov:contentFormat"] ?? form.contentType ?? "application/json";
+        const contentFormat = form["cov:contentFormat"] ?? form.contentType;
         debug(`"CoapClient got Form 'contentType' ${contentFormat} `);
 
         const accept = form["cov:accept"];

packages/binding-coap/src/coap-server.ts

@@ -939,7 +939,7 @@ export default class CoapServer implements ProtocolServer {
             );
         }
 
-        return contentType ?? ContentSerdes.DEFAULT;
+        return contentType;
     }
 
     private checkContentTypeSupportForInput(method: string, contentType: string): boolean {

packages/binding-coap/src/coaps-client.ts

@@ -47,7 +47,7 @@ export default class CoapsClient implements ProtocolClient {
                     debug(`CoapsClient received ${res.code} from ${form.href}`);
 
                     // FIXME: Add toString conversion for response Content-Format
-                    const contentType = form.contentType ?? ContentSerdes.DEFAULT;
+                    const contentType = form.contentType;
                     const body = Readable.from(res.payload ?? Buffer.alloc(0));
 
                     resolve(new Content(contentType, body));
@@ -79,7 +79,7 @@ export default class CoapsClient implements ProtocolClient {
                     debug(`CoapsClient received ${res.code} from ${form.href}`);
 
                     // FIXME: Add toString conversion for response Content-Format
-                    const contentType = form.contentType ?? ContentSerdes.DEFAULT;
+                    const contentType = form.contentType;
                     const body = Readable.from(res.payload ?? Buffer.alloc(0));
 
                     resolve(new Content(contentType, body));
@@ -118,7 +118,7 @@ export default class CoapsClient implements ProtocolClient {
 
             const callback = (resp: CoapResponse) => {
                 if (resp.payload != null) {
-                    next(new Content(form?.contentType ?? ContentSerdes.DEFAULT, Readable.from(resp.payload)));
+                    next(new Content(form?.contentType, Readable.from(resp.payload)));
                 }
             };
 

packages/binding-http/src/subscription-protocols.ts

@@ -117,7 +117,7 @@ export class SSESubscription implements InternalSubscription {
             };
             this.eventSource.onmessage = (event) => {
                 debug(`HttpClient received ${JSON.stringify(event)} from ${this.form.href}`);
-                const output = new Content(this.form.contentType ?? ContentSerdes.DEFAULT, Readable.from(event.data));
+                const output = new Content(this.form.contentType, Readable.from(event.data));
                 next(output);
             };
             this.eventSource.onerror = function (event) {

packages/binding-modbus/src/modbus-connection.ts

@@ -451,7 +451,7 @@ export class PropertyOperation {
         this.quantity = form["modv:quantity"];
         this.function = form["modv:function"] as ModbusFunction;
         this.endianness = endianness;
-        this.contentType = form.contentType ?? ContentSerdes.DEFAULT;
+        this.contentType = form.contentType;
         this.content = content;
         this.transaction = null;
     }

packages/binding-mqtt/src/mqtt-broker-server.ts

@@ -263,7 +263,7 @@ export default class MqttBrokerServer implements ProtocolServer {
          * https://github.com/mqttjs/MQTT.js/pull/1103
          * For further discussion see https://github.com/eclipse-thingweb/node-wot/pull/253
          */
-        const contentType = packet?.properties?.contentType ?? ContentSerdes.DEFAULT;
+        const contentType = packet?.properties?.contentType;
 
         const options: InteractionOptions & { formIndex: number } = {
             formIndex: ProtocolHelpers.findRequestMatchingFormIndex(
@@ -274,7 +274,7 @@ export default class MqttBrokerServer implements ProtocolServer {
             ),
         };
 
-        const formContentType = action.forms[options.formIndex].contentType ?? ContentSerdes.DEFAULT;
+        const formContentType = action.forms[options.formIndex].contentType;
         const inputContent = new Content(formContentType, Readable.from(payload));
 
         thing
@@ -306,7 +306,7 @@ export default class MqttBrokerServer implements ProtocolServer {
     ) {
         const readOnly = property.readOnly ?? false;
         if (!readOnly) {
-            const contentType = packet?.properties?.contentType ?? ContentSerdes.DEFAULT;
+            const contentType = packet?.properties?.contentType;
 
             const options: InteractionOptions & { formIndex: number } = {
                 formIndex: ProtocolHelpers.findRequestMatchingFormIndex(
@@ -317,7 +317,7 @@ export default class MqttBrokerServer implements ProtocolServer {
                 ),
             };
 
-            const formContentType = property.forms[options.formIndex].contentType ?? ContentSerdes.DEFAULT;
+            const formContentType = property.forms[options.formIndex].contentType;
             const inputContent = new Content(formContentType, Readable.from(payload));
 
             try {

packages/binding-mqtt/src/mqtt-client.ts

@@ -50,7 +50,7 @@ export default class MqttClient implements ProtocolClient {
         error?: (error: Error) => void,
         complete?: () => void
     ): Promise<Subscription> {
-        const contentType = form.contentType ?? ContentSerdes.DEFAULT;
+        const contentType = form.contentType;
         const requestUri = new url.URL(form.href);
         const brokerUri: string = `${this.scheme}://` + requestUri.host;
         // Keeping the path as the topic for compatibility reasons.

packages/binding-opcua/src/opcua-protocol-client.ts

@@ -466,7 +466,7 @@ export class OPCUAProtocolClient implements ProtocolClient {
 
     ///
     private async _dataValueToContent(form: OPCUAForm, dataValue: DataValue): Promise<Content> {
-        const contentType = form.contentType ?? "application/json";
+        const contentType = form.contentType;
 
         // QUESTION: how can we extend the default contentSerDes.valueToContent for application/json,
         const contentSerDes = ContentSerdes.get();
@@ -615,13 +615,11 @@ export class OPCUAProtocolClient implements ProtocolClient {
     ): Promise<Content> {
         const outputArguments = (argumentDefinition.outputArguments ?? []) as unknown as Argument[];
 
-        const contentType = form.contentType ?? "application/json";
-
         const body: Record<string, unknown> = {};
         for (let index = 0; index < outputArguments.length; index++) {
             const argument = outputArguments[index];
             const { name } = argument;
-            const element = _variantToJSON(outputVariants[index], contentType);
+            const element = _variantToJSON(outputVariants[index], form.contentType);
             body[name ?? "null"] = element;
         }
 

packages/core/src/exposed-thing.ts

@@ -409,11 +409,7 @@ export default class ExposedThing extends TD.Thing implements WoT.ExposedThing {
                 const form = this.properties[propertyName]?.forms[options.formIndex] ?? {
                     contentType: "application/json",
                 };
-                return ContentManager.valueToContent(
-                    result,
-                    this.properties[propertyName],
-                    form?.contentType ?? "application/json"
-                );
+                return ContentManager.valueToContent(result, this.properties[propertyName], form.contentType);
             } else {
                 throw new Error(`ExposedThing '${this.title}' has no readHandler for Property '${propertyName}'`);
             }

packages/td-tools/src/thing-description.ts

@@ -56,7 +56,7 @@ export type ThingInteraction = TDT.PropertyElement | TDT.ActionElement | TDT.Eve
 export class Form implements TDT.FormElementBase {
     op?: string | string[];
     href: TDT.AnyUri;
-    contentType?: string;
+    contentType: string;
     contentCoding?: string;
     subprotocol?: TDT.Subprotocol;
     security?: TDT.Security;
@@ -67,7 +67,7 @@ export class Form implements TDT.FormElementBase {
 
     constructor(href: string, contentType?: string) {
         this.href = href;
-        if (contentType != null) this.contentType = contentType;
+        this.contentType = contentType ?? "application/json";
     }
 }
 export interface ExpectedResponse {