[api-minor] Add "contentLength" to the information returned by the `g…

…etMetadata` method

Given that we already include the "Content-Disposition"-header filename, when it exists, it shouldn't hurt to also include the information from the "Content-Length"-header.
For PDF documents opened via a URL, which should be a very common way for the PDF.js library to be used, this will[1] thus provide a way of getting the PDF filesize without having to wait for the `getDownloadInfo`-promise to resolve[2].

With these API improvements, we can also simplify the filesize handling in the `PDFDocumentProperties` class.

---
[1] Assuming that the server is correctly configured, of course.

[2] Since that's not *guaranteed* to happen in general, with e.g. `disableAutoFetch = true` set.

src/display/api.js

@@ -2654,9 +2654,8 @@ class WorkerTransport {
         return {
           info: results[0],
           metadata: results[1] ? new Metadata(results[1]) : null,
-          contentDispositionFilename: this._fullReader
-            ? this._fullReader.filename
-            : null,
+          contentDispositionFilename: this._fullReader?.filename ?? null,
+          contentLength: this._fullReader?.contentLength ?? null,
         };
       });
   }

test/unit/api_spec.js

@@ -1132,7 +1132,12 @@ describe("api", function () {
     it("gets metadata", function (done) {
       const promise = pdfDocument.getMetadata();
       promise
-        .then(function ({ info, metadata, contentDispositionFilename }) {
+        .then(function ({
+          info,
+          metadata,
+          contentDispositionFilename,
+          contentLength,
+        }) {
           expect(info.Title).toEqual("Basic API Test");
           // Custom, non-standard, information dictionary entries.
           expect(info.Custom).toEqual(undefined);
@@ -1147,6 +1152,7 @@ describe("api", function () {
           expect(metadata.get("dc:title")).toEqual("Basic API Test");
 
           expect(contentDispositionFilename).toEqual(null);
+          expect(contentLength).toEqual(basicApiFileLength);
           done();
         })
         .catch(done.fail);
@@ -1160,7 +1166,12 @@ describe("api", function () {
         .then(function (pdfDoc) {
           return pdfDoc.getMetadata();
         })
-        .then(function ({ info, metadata, contentDispositionFilename }) {
+        .then(function ({
+          info,
+          metadata,
+          contentDispositionFilename,
+          contentLength,
+        }) {
           expect(info.Creator).toEqual("TeX");
           expect(info.Producer).toEqual("pdfeTeX-1.21a");
           expect(info.CreationDate).toEqual("D:20090401163925-07'00'");
@@ -1181,6 +1192,7 @@ describe("api", function () {
 
           expect(metadata).toEqual(null);
           expect(contentDispositionFilename).toEqual(null);
+          expect(contentLength).toEqual(1016315);
 
           loadingTask.destroy().then(done);
         })
@@ -1193,7 +1205,12 @@ describe("api", function () {
         .then(function (pdfDoc) {
           return pdfDoc.getMetadata();
         })
-        .then(function ({ info, metadata, contentDispositionFilename }) {
+        .then(function ({
+          info,
+          metadata,
+          contentDispositionFilename,
+          contentLength,
+        }) {
           // The following are PDF.js specific, non-standard, properties.
           expect(info.PDFFormatVersion).toEqual(null);
           expect(info.IsLinearized).toEqual(false);
@@ -1203,6 +1220,7 @@ describe("api", function () {
 
           expect(metadata).toEqual(null);
           expect(contentDispositionFilename).toEqual(null);
+          expect(contentLength).toEqual(624);
 
           loadingTask.destroy().then(done);
         })

web/app.js

@@ -863,15 +863,10 @@ const PDFViewerApplication = {
       }
       parameters[key] = value;
     }
-
+    // Finally, update the API parameters with the arguments (if they exist).
     if (args) {
       for (const key in args) {
-        const value = args[key];
-
-        if (key === "length") {
-          this.pdfDocumentProperties.setFileSize(value);
-        }
-        parameters[key] = value;
+        parameters[key] = args[key];
       }
     }
 

web/pdf_document_properties.js

@@ -128,23 +128,25 @@ class PDFDocumentProperties {
       // Get the document properties.
       this.pdfDocument
         .getMetadata()
-        .then(({ info, metadata, contentDispositionFilename }) => {
-          return Promise.all([
-            info,
-            metadata,
-            contentDispositionFilename || getPDFFileNameFromURL(this.url),
-            this._parseFileSize(this.maybeFileSize),
-            this._parseDate(info.CreationDate),
-            this._parseDate(info.ModDate),
-            this.pdfDocument.getPage(currentPageNumber).then(pdfPage => {
-              return this._parsePageSize(
-                getPageSizeInches(pdfPage),
-                pagesRotation
-              );
-            }),
-            this._parseLinearization(info.IsLinearized),
-          ]);
-        })
+        .then(
+          ({ info, metadata, contentDispositionFilename, contentLength }) => {
+            return Promise.all([
+              info,
+              metadata,
+              contentDispositionFilename || getPDFFileNameFromURL(this.url),
+              this._parseFileSize(contentLength),
+              this._parseDate(info.CreationDate),
+              this._parseDate(info.ModDate),
+              this.pdfDocument.getPage(currentPageNumber).then(pdfPage => {
+                return this._parsePageSize(
+                  getPageSizeInches(pdfPage),
+                  pagesRotation
+                );
+              }),
+              this._parseLinearization(info.IsLinearized),
+            ]);
+          }
+        )
         .then(
           ([
             info,
@@ -176,15 +178,13 @@ class PDFDocumentProperties {
             });
             this._updateUI();
 
-            // Get the correct fileSize, since it may not have been set (if
-            // `this.setFileSize` wasn't called) or may be incorrectly set.
-            return this.pdfDocument.getDownloadInfo();
+            // Get the correct fileSize, since it may not have been available
+            // or could potentially be wrong.
+            return this.pdfDocument.getDownloadInfo().then(downloadInfo => {
+              return this._parseFileSize(downloadInfo.length);
+            });
           }
         )
-        .then(({ length }) => {
-          this.maybeFileSize = length;
-          return this._parseFileSize(length);
-        })
         .then(fileSize => {
           if (fileSize === this.fieldData.fileSize) {
             return; // The fileSize has already been correctly set.
@@ -228,27 +228,13 @@ class PDFDocumentProperties {
     this._dataAvailableCapability.resolve();
   }
 
-  /**
-   * Set the file size of the PDF document. This method is used to
-   * update the file size in the document properties overlay once it
-   * is known so we do not have to wait until the entire file is loaded.
-   *
-   * @param {number} fileSize - The file size of the PDF document.
-   */
-  setFileSize(fileSize) {
-    if (Number.isInteger(fileSize) && fileSize > 0) {
-      this.maybeFileSize = fileSize;
-    }
-  }
-
   /**
    * @private
    */
   _reset() {
     this.pdfDocument = null;
     this.url = null;
 
-    this.maybeFileSize = 0;
     delete this.fieldData;
     this._dataAvailableCapability = createPromiseCapability();
     this._currentPageNumber = 1;