Add MWG and MD5 support.

- put ExifTool on a diet--extract several interfaces and consts into their own new file
- add options support to both read and write tasks
- fix typing warnings by exporting Literal/Json
- add ImageDataMD5 tests
- add MWG read/write round trip tests

src/DefaultExifToolOptions.ts

@@ -0,0 +1,50 @@
+import * as bc from "batch-cluster"
+import { DefaultExiftoolArgs } from "./DefaultExiftoolArgs"
+import { DefaultMaxProcs } from "./DefaultMaxProcs"
+import { ExifToolOptions } from "./ExifToolOptions"
+import { DefaultExifToolPath } from "./FindExiftool"
+import { geoTz } from "./GeoTz"
+import { isIgnorableWarning } from "./IgnorableError"
+import { Omit } from "./Omit"
+import { VersionTask } from "./VersionTask"
+
+/**
+ * Default values for `ExifToolOptions`, except for `processFactory` (which is
+ * created by the ExifTool constructor)
+ */
+
+export const DefaultExifToolOptions: Omit<
+  ExifToolOptions,
+  "processFactory" | "ignoreShebang"
+> = Object.freeze({
+  ...new bc.BatchClusterOptions(),
+  maxProcs: DefaultMaxProcs,
+  maxTasksPerProcess: 500,
+  spawnTimeoutMillis: 30000,
+  // see https://github.com/photostructure/exiftool-vendored.js/issues/34 :
+  taskTimeoutMillis: 20000,
+  onIdleIntervalMillis: 2000,
+  taskRetries: 1,
+  exiftoolPath: DefaultExifToolPath,
+  exiftoolArgs: DefaultExiftoolArgs,
+  exiftoolEnv: {},
+  pass: "{ready}",
+  fail: "{ready}",
+  exitCommand: "-stay_open\nFalse\n",
+  versionCommand: new VersionTask().command,
+  healthCheckIntervalMillis: 30000,
+  healthCheckCommand: "-ver\n-execute\n",
+  useMWG: false,
+  numericTags: [
+    "*Duration*",
+    "GPSAltitude",
+    "GPSLatitude",
+    "GPSLongitude",
+    "GPSPosition",
+    "Orientation",
+  ],
+  includeImageDataMD5: false,
+  defaultVideosToUTC: true,
+  geoTz: geoTz,
+  isIgnorableError: isIgnorableWarning,
+})

src/DefaultExiftoolArgs.ts

@@ -0,0 +1 @@
+export const DefaultExiftoolArgs = ["-stay_open", "True", "-@", "-"]

src/DefaultMaxProcs.ts

@@ -0,0 +1,3 @@
+import * as _os from "os"
+
+export const DefaultMaxProcs = Math.max(1, Math.floor(_os.cpus().length / 4))

src/ExifTool.spec.ts

@@ -2,10 +2,11 @@ import { BatchCluster } from "batch-cluster"
 import * as _path from "path"
 import { times } from "./Array"
 import { BinaryField } from "./BinaryField"
+import { DefaultMaxProcs } from "./DefaultMaxProcs"
 import { ExifDate } from "./ExifDate"
 import { ExifDateTime } from "./ExifDateTime"
 import { ExifTime } from "./ExifTime"
-import { DefaultMaxProcs, ExifTool, exiftool } from "./ExifTool"
+import { ExifTool, exiftool } from "./ExifTool"
 import { isWin32 } from "./IsWin32"
 import { parseJSON } from "./JSON"
 import { fromEntries, keys } from "./Object"
@@ -313,10 +314,8 @@ describe("ExifTool", function () {
 
       it("reads from a dSLR", async () => {
         const t = await et.read("./test/oly.jpg")
-        expect(renderTagsWithISO(t)).to.contain({
+        expect(renderTagsWithISO(t)).to.containSubset({
           Aperture: 5,
-          Artist: "",
-          Copyright: "",
           CreateDate: "2014-07-19T12:05:19-07:00",
           DateTimeOriginal: "2014-07-19T12:05:19-07:00",
           ExifImageHeight: 2400,
@@ -333,6 +332,7 @@ describe("ExifTool", function () {
           Model: "E-M1",
           ModifyDate: "2014-07-19T12:05:19-07:00",
           Orientation: 1,
+          SensorTemperature: "80.3 C",
           tz: "UTC-7",
           tzSource: "offset between DateTimeOriginal and DateTimeUTC",
         })

src/ExifTool.ts

@@ -1,29 +1,30 @@
 import * as bc from "batch-cluster"
 import * as _cp from "child_process"
 import * as _fs from "fs"
-import * as _os from "os"
-import * as _path from "path"
 import process from "process"
 import { ApplicationRecordTags } from "./ApplicationRecordTags"
 import { retryOnReject } from "./AsyncRetry"
 import { BinaryExtractionTask } from "./BinaryExtractionTask"
 import { BinaryToBufferTask } from "./BinaryToBufferTask"
+import { DefaultExiftoolArgs } from "./DefaultExiftoolArgs"
+import { DefaultExifToolOptions } from "./DefaultExifToolOptions"
+import { DefaultMaxProcs } from "./DefaultMaxProcs"
 import { DeleteAllTagsArgs } from "./DeleteAllTagsArgs"
 import { ExifDate } from "./ExifDate"
 import { ExifDateTime } from "./ExifDateTime"
 import { ExifToolOptions } from "./ExifToolOptions"
 import { ExifToolTask } from "./ExifToolTask"
-import { geoTz } from "./GeoTz"
 import { ICCProfileTags } from "./ICCProfileTags"
-import { IgnorableError, isIgnorableWarning } from "./IgnorableError"
+import { IgnorableError } from "./IgnorableError"
 import { isWin32 } from "./IsWin32"
 import { lazy } from "./Lazy"
 import { Maybe } from "./Maybe"
 import { Omit } from "./Omit"
+import { pick } from "./Pick"
 import { PreviewTag } from "./PreviewTag"
-import { RawTags } from "./RawTags"
+import { Json, Literal, RawTags } from "./RawTags"
 import { ReadRawTask } from "./ReadRawTask"
-import { ReadTask } from "./ReadTask"
+import { DefaultReadTaskOptions, ReadTask, ReadTaskOptions } from "./ReadTask"
 import { ResourceEvent } from "./ResourceEvent"
 import { RewriteAllTagsTask } from "./RewriteAllTagsTask"
 import { blank, notBlank } from "./String"
@@ -42,9 +43,9 @@ import {
   FlashPixTags,
   IPTCTags,
   JFIFTags,
-  MPFTags,
   MakerNotesTags,
   MetaTags,
+  MPFTags,
   PanasonicRawTags,
   PhotoshopTags,
   PrintIMTags,
@@ -56,7 +57,12 @@ import {
 } from "./Tags"
 import { Version } from "./Version"
 import { VersionTask } from "./VersionTask"
-import { WriteTask } from "./WriteTask"
+import { WriteTags } from "./WriteTags"
+import {
+  DefaultWriteTaskOptions,
+  WriteTask,
+  WriteTaskOptions,
+} from "./WriteTask"
 
 export { BinaryField } from "./BinaryField"
 export { ExifDate } from "./ExifDate"
@@ -66,11 +72,11 @@ export { ExifToolTask } from "./ExifToolTask"
 export { isIgnorableWarning } from "./IgnorableError"
 export { parseJSON } from "./JSON"
 export {
+  defaultVideosToUTC,
+  offsetMinutesToZoneName,
   UnsetZone,
   UnsetZoneName,
   UnsetZoneOffsetMinutes,
-  defaultVideosToUTC,
-  offsetMinutesToZoneName,
 } from "./Timezones"
 export type {
   AdditionalWriteTags,
@@ -82,6 +88,11 @@ export type {
   APP6Tags,
   ApplicationRecordTags,
   CompositeTags,
+  DefaultExiftoolArgs,
+  DefaultExifToolOptions,
+  DefaultMaxProcs,
+  DefaultReadTaskOptions,
+  DefaultWriteTaskOptions,
   EXIFTags,
   ExifToolOptions,
   ExifToolTags,
@@ -92,6 +103,8 @@ export type {
   IgnorableError,
   IPTCTags,
   JFIFTags,
+  Json,
+  Literal,
   MakerNotesTags,
   Maybe,
   MetaTags,
@@ -103,44 +116,17 @@ export type {
   QuickTimeTags,
   RAFTags,
   RawTags,
+  ReadTaskOptions,
   ResourceEvent,
   RIFFTags,
   Struct,
   Tags,
   Version,
+  WriteTags,
+  WriteTaskOptions,
   XMPTags,
 }
 
-function findExiftool(): string {
-  const path: string = require(`exiftool-vendored.${isWin32() ? "exe" : "pl"}`)
-  // This s/app.asar/app.asar.unpacked/ path switch adds support for Electron
-  // apps that are ASAR-packed.
-
-  // Note that we can't check for electron because child processes that are
-  // spawned by the main process will most likely need the ELECTRON_RUN_AS_NODE
-  // environment variable set, which will unset the process.versions.electron
-  // field.
-  const fixedPath = path
-    .split(_path.sep)
-    .map((ea) => (ea === "app.asar" ? "app.asar.unpacked" : ea))
-    .join(_path.sep)
-
-  // Note also, that we must check for the fixedPath first, because Electron's
-  // ASAR shenanigans will make existsSync return true even for asar-packed
-  // resources.
-  if (_fs.existsSync(fixedPath)) {
-    return fixedPath
-  }
-  if (_fs.existsSync(path)) {
-    return path
-  }
-  throw new Error(`Vendored ExifTool does not exist at ${path}`)
-}
-
-export const DefaultExifToolPath = findExiftool()
-
-export const DefaultExiftoolArgs = ["-stay_open", "True", "-@", "-"]
-
 const _ignoreShebang = lazy(
   () => !isWin32() && !_fs.existsSync("/usr/bin/perl")
 )
@@ -190,50 +176,6 @@ export interface StructAppendTags {
   "Versions+"?: Version | Version[]
 }
 
-export type WriteTags = DefinedOrNullValued<
-  ShortcutTags & AdditionalWriteTags & ExpandedDateTags & StructAppendTags
->
-
-export const DefaultMaxProcs = Math.max(1, Math.floor(_os.cpus().length / 4))
-
-/**
- * Default values for `ExifToolOptions`, except for `processFactory` (which is
- * created by the ExifTool constructor)
- */
-export const DefaultExifToolOptions: Omit<
-  ExifToolOptions,
-  "processFactory" | "ignoreShebang"
-> = Object.freeze({
-  ...new bc.BatchClusterOptions(),
-  maxProcs: DefaultMaxProcs,
-  maxTasksPerProcess: 500,
-  spawnTimeoutMillis: 30_000,
-  // see https://github.com/photostructure/exiftool-vendored.js/issues/34 :
-  taskTimeoutMillis: 20_000,
-  onIdleIntervalMillis: 2_000,
-  taskRetries: 1,
-  exiftoolPath: DefaultExifToolPath,
-  exiftoolArgs: DefaultExiftoolArgs,
-  exiftoolEnv: {},
-  pass: "{ready}",
-  fail: "{ready}", // < not used
-  exitCommand: "-stay_open\nFalse\n",
-  versionCommand: new VersionTask().command,
-  healthCheckIntervalMillis: 30_000,
-  healthCheckCommand: "-ver\n-execute\n",
-  numericTags: [
-    "*Duration*",
-    "GPSAltitude",
-    "GPSLatitude",
-    "GPSLongitude",
-    "GPSPosition",
-    "Orientation",
-  ],
-  defaultVideosToUTC: true,
-  geoTz: geoTz,
-  isIgnorableError: isIgnorableWarning,
-})
-
 /**
  * Manages delegating calls to a vendored running instance of ExifTool.
  *
@@ -300,50 +242,63 @@ export class ExifTool {
    * Read the tags in `file`.
    *
    * @param {string} file the file to extract metadata tags from
-   * @param {string[]} [optionalArgs] any additional ExifTool arguments, like "-fast" or
-   * "-fast2". **Most other arguments will require you to use `readRaw`.**
-   * Note that the default is "-fast", so if you want ExifTool to read the
-   * entire file for metadata, you should pass an empty array as the second
-   * parameter. See https://exiftool.org/#performance for
-   * more information about `-fast` and `-fast2`.
+   *
+   * @param {string[]} [optionalArgs] any additional ExifTool arguments, like
+   * "-fast" or "-fast2". **Most other arguments will require you to use
+   * `readRaw`.** Note that the default is "-fast", so if you want ExifTool to
+   * read the entire file for metadata, you should pass an empty array as the
+   * second parameter. See https://exiftool.org/#performance for more
+   * information about `-fast` and `-fast2`.
+   *
    * @returns {Promise<Tags>} A resolved Tags promise. If there are errors
    * during reading, the `.errors` field will be present.
-   * @memberof ExifTool
    */
   read<T extends Tags = Tags>(
     file: string,
-    optionalArgs: string[] = ["-fast"]
+    optionalArgs: string[] = ["-fast"],
+    options?: ReadTaskOptions
   ): Promise<T> {
     return this.enqueueTask(() =>
       ReadTask.for(file, {
         optionalArgs,
-        numericTags: this.options.numericTags,
-        defaultVideosToUTC: this.options.defaultVideosToUTC,
-        geoTz: this.options.geoTz,
+        ...pick(
+          this.options,
+          "numericTags",
+          "useMWG",
+          "includeImageDataMD5",
+          "defaultVideosToUTC",
+          "geoTz"
+        ),
+        ...options,
       })
     ) as any // < no way to know at compile time if we're going to get back a T!
   }
 
   /**
-   * Read the tags from `file`, without any post-processing of ExifTool values.
+   * Read the tags from `file`, without any post-processing of ExifTool
+   * values.
    *
-   * **You probably want `read`, not this method. READ THE REST OF THIS COMMENT
-   * CAREFULLY.**
+   * **You probably want `read`, not this method. READ THE REST OF THIS
+   * COMMENT CAREFULLY.**
    *
-   * If you want to extract specific tag values from a file, you may want to use
-   * this, but all data validation and inference heuristics provided by `read`
-   * will be skipped.
+   * If you want to extract specific tag values from a file, you may want to
+   * use this, but all data validation and inference heuristics provided by
+   * `read` will be skipped.
    *
-   * Note that performance will be very similar to `read`, and will actually be
-   * worse if you don't include `-fast` or `-fast2` (as the most expensive bit
-   * is the perl interpreter and scanning the file on disk).
+   * Note that performance will be very similar to `read`, and will actually
+   * be worse if you don't include `-fast` or `-fast2` (as the most expensive
+   * bit is the perl interpreter and scanning the file on disk).
    *
-   * @param args any additional arguments other than the file path. Note that "-json", and the Windows unicode filename handler flags, "-charset filename=utf8", will be added automatically.
+   * @param args any additional arguments other than the file path. Note that
+   * "-json", and the Windows unicode filename handler flags, "-charset
+   * filename=utf8", will be added automatically.
    *
    * @return Note that the return value will be similar to `Tags`, but with no
-   * date, time, or other rich type parsing that you get from `.read()`. The field values will be `string | number | string[]`.
+   * date, time, or other rich type parsing that you get from `.read()`. The
+   * field values will be `string | number | string[]`.
    *
-   * @see https://github.com/photostructure/exiftool-vendored.js/issues/44
+   * @see https://github.com/photostructure/exiftool-vendored.js/issues/44 for
+   * typing details.
    */
   readRaw(file: string, args: string[] = []): Promise<RawTags> {
     return this.enqueueTask(() => ReadRawTask.for(file, args))
@@ -361,9 +316,21 @@ export class ExifTool {
    * there are errors or warnings.
    * @memberof ExifTool
    */
-  write(file: string, tags: WriteTags, args?: string[]): Promise<void> {
+  write(
+    file: string,
+    tags: WriteTags,
+    args?: string[],
+    options?: WriteTaskOptions
+  ): Promise<void> {
     const retriable = false
-    return this.enqueueTask(() => WriteTask.for(file, tags, args), retriable)
+    return this.enqueueTask(
+      () =>
+        WriteTask.for(file, tags, args, {
+          ...pick(this.options, "useMWG"),
+          ...options,
+        }),
+      retriable
+    )
   }
 
   /**