refactor crate versions

Author: nyurik

services/crates/crates-base.js

@@ -1,6 +1,6 @@
 import Joi from 'joi'
 import { nonNegativeInteger } from '../validators.js'
-import { BaseJsonService } from '../index.js'
+import { BaseJsonService, InvalidParameter } from '../index.js'
 
 const keywords = ['Rust']
 
@@ -47,6 +47,45 @@ class BaseCratesService extends BaseJsonService {
       : `https://crates.io/api/v1/crates/${crate}?include=versions,downloads`
     return this._requestJson({ schema, url })
   }
+
+  /** get the default version for a crate using the same logic as crates.io
+   * this should be kept in sync with the crates.io implementation in
+   * https://github.com/rust-lang/crates.io/blob/20bbac9f5521cb4888ef63f8464fddb28fd973f5/app/models/crate.js#L34-L41
+   *
+   * @param {object} crate the `json.crate` response from crates.io
+   * @returns {string} the default version string, or throws an error
+   */
+  static defaultVersion(crate) {
+    if (crate) {
+      if (crate.max_stable_version) {
+        return crate.max_stable_version
+      }
+      if (crate.max_version && crate.max_version !== '0.0.0') {
+        return crate.max_version
+      }
+    }
+    throw new InvalidParameter({
+      prettyMessage:
+        'default version not found, possibly all versions were yanked',
+    })
+  }
+
+  /** get the default version object from the `json.versions` array.
+   *
+   * @param {object} crate the `json.crate` response from crates.io
+   * @param {object[]} versions the `json.versions` response from crates.io
+   * @returns {object} the default version object, or throws an error if not found
+   */
+  static defaultVersionObject(crate, versions) {
+    const lastVerNum = BaseCratesService.defaultVersion(crate)
+    const version = versions.find(ver => ver.num === lastVerNum)
+    if (!version) {
+      throw new InvalidParameter({
+        prettyMessage: 'version object not found in the versions array',
+      })
+    }
+    return version
+  }
 }
 
 export { BaseCratesService, keywords }

services/crates/crates-downloads.service.js

@@ -68,16 +68,14 @@ export default class CratesDownloads extends BaseCratesService {
   transform({ variant, json }) {
     switch (variant) {
       case 'dv':
-        let lastVer = json.version
         if (json.crate) {
-          const lastVerNum = json.crate.max_stable_version
-            ? json.crate.max_stable_version
-            : json.crate.max_version
-          lastVer =
-            json.versions.find(ver => ver.num === lastVerNum) ||
-            json.versions[0]
+          return BaseCratesService.defaultVersionObject(
+            json.crate,
+            json.versions,
+          ).downloads
+        } else {
+          return json.version.downloads
         }
-        return lastVer.downloads
       case 'dr':
         return json.crate.recent_downloads || 0
       default:

services/crates/crates-license.service.js

@@ -28,24 +28,16 @@ export default class CratesLicense extends BaseCratesService {
     return { message }
   }
 
-  static transform({ errors, version, versions, crate }) {
+  static transform({ errors, version, crate, versions }) {
     // crates.io returns a 200 response with an errors object in
     // error scenarios, e.g. https://crates.io/api/v1/crates/libc/0.1
     if (errors) {
       throw new InvalidResponse({ prettyMessage: errors[0].detail })
     }
 
-    let license
-    if (version) {
-      license = version.license
-    } else {
-      const lastVerNum = crate.max_stable_version
-        ? crate.max_stable_version
-        : crate.max_version
-      const lastVer =
-        versions.find(ver => ver.num === lastVerNum) || versions[0]
-      license = lastVer.license
-    }
+    const license = version
+      ? version.license
+      : BaseCratesService.defaultVersionObject(crate, versions).license
 
     if (!license) {
       throw new InvalidResponse({ prettyMessage: 'invalid null license' })

services/crates/crates-license.spec.js

@@ -6,11 +6,13 @@ import CratesLicense from './crates-license.service.js'
 describe('CratesLicense', function () {
   test(CratesLicense.transform, () => {
     given({
+      crate: { max_stable_version: '1.0.0', max_version: '1.0.0' },
       version: { num: '1.0.0', license: 'MIT' },
-      versions: [{ license: 'MIT/Apache 2.0' }],
+      versions: [{ num: '1.0.0', license: 'MIT/Apache 2.0' }],
     }).expect({ license: 'MIT' })
     given({
-      versions: [{ license: 'MIT/Apache 2.0' }],
+      crate: { max_stable_version: '1.0.0', max_version: '1.0.0' },
+      versions: [{ num: '1.0.0', license: 'MIT/Apache 2.0' }],
     }).expect({ license: 'MIT/Apache 2.0' })
   })
 
@@ -31,7 +33,12 @@ describe('CratesLicense', function () {
   })
 
   it('throws InvalidResponse on null license with latest version', function () {
-    expect(() => CratesLicense.transform({ versions: [{ license: null }] }))
+    expect(() =>
+      CratesLicense.transform({
+        crate: { max_stable_version: '1.0.0', max_version: '1.0.0' },
+        versions: [{ num: '1.0.0', license: null }],
+      }),
+    )
       .to.throw(InvalidResponse)
       .with.property('prettyMessage', 'invalid null license')
   })

services/crates/crates-version.service.js

@@ -19,9 +19,7 @@ export default class CratesVersion extends BaseCratesService {
     if (json.errors) {
       throw new InvalidResponse({ prettyMessage: json.errors[0].detail })
     }
-    return json.crate.max_stable_version
-      ? json.crate.max_stable_version
-      : json.crate.max_version
+    return BaseCratesService.defaultVersion(json.crate)
   }
 
   async handle({ crate }) {