newerton · October 12, 2024 23:11 · Sep 5, 2019 · Sep 5, 2019 · Sep 4, 2019
diff --git a/FileUploadDataSource.js b/FileUploadDataSource.js
@@ -21,7 +21,7 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
     // https://github.com/jaydenseric/graphql-multipart-request-spec
     const form = new FormData();
 
-    //cannot mutate the orginal request
+    // cannot mutate the request object
     const variables = _.cloneDeep(request.variables);
     for (const [variableName] of fileVariables) {
       _.set(variables, variableName, null);
@@ -31,7 +31,7 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
       query: request.query,
       variables,
     });
-    
+
     form.append('operations', operations);
 
     const resolvedFiles = await Promise.all(
@@ -55,6 +55,7 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
       resolvedFiles.map(async ([, contents], i) => {
         const { filename, mimetype, createReadStream } = contents;
         const readStream = await createReadStream();
+        // TODO: Buffers performance issues? may be better solution.
         const buffer = await this.onReadStream(readStream);
         form.append(i, buffer, { filename, contentType: mimetype });
       })
@@ -116,6 +117,7 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
         if (value instanceof Promise) {
           return files.push([key, value]);
         }
+        // TODO: support arrays of files
         if (value instanceof Object) {
           return _extract(value, key);
         }

diff --git a/FileUploadDataSource.js b/FileUploadDataSource.js
@@ -5,7 +5,7 @@ import FormData from 'form-data';
 import _ from 'lodash';
 
 export default class FileUploadDataSource extends RemoteGraphQLDataSource {
-  process(args) {
+  async process(args) {
     const { request, context } = args;
 
     const fileVariables = this.extract(request.variables);
@@ -21,7 +21,8 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
     // https://github.com/jaydenseric/graphql-multipart-request-spec
     const form = new FormData();
 
-    const variables = request.variables;
+    //cannot mutate the orginal request
+    const variables = _.cloneDeep(request.variables);
     for (const [variableName] of fileVariables) {
       _.set(variables, variableName, null);
     }
@@ -30,6 +31,7 @@ export default class FileUploadDataSource extends RemoteGraphQLDataSource {
       query: request.query,
       variables,
     });
+
     form.append('operations', operations);
 
     const resolvedFiles = await Promise.all(

diff --git a/FileUploadDataSource.js b/FileUploadDataSource.js
@@ -0,0 +1,140 @@
+import { RemoteGraphQLDataSource } from '@apollo/gateway';
+import { fetch, Request, Headers } from 'apollo-server-env';
+import { isObject } from '@apollo/gateway/dist/utilities/predicates';
+import FormData from 'form-data';
+import _ from 'lodash';
+
+export default class FileUploadDataSource extends RemoteGraphQLDataSource {
+  process(args) {
+    const { request, context } = args;
+
+    const fileVariables = this.extract(request.variables);
+    if (fileVariables.length > 0) {
+      return this.processFileUpload(args, fileVariables);
+    } else {
+      return super.process(args);
+    }
+  }
+
+  async processFileUpload({ request, context }, fileVariables) {
+    // GraphQL multipart request spec:
+    // https://github.com/jaydenseric/graphql-multipart-request-spec
+    const form = new FormData();
+
+    const variables = request.variables;
+    for (const [variableName] of fileVariables) {
+      _.set(variables, variableName, null);
+    }
+
+    const operations = JSON.stringify({
+      query: request.query,
+      variables,
+    });
+    form.append('operations', operations);
+
+    const resolvedFiles = await Promise.all(
+      fileVariables.map(async ([variableName, file]) => {
+        const contents = await file;
+        return [variableName, contents];
+      })
+    );
+
+    // e.g. { "0": ["variables.file"] }
+    const fileMap = resolvedFiles.reduce(
+      (map, [variableName], i) => ({
+        ...map,
+        [i]: [`variables.${variableName}`],
+      }),
+      {}
+    );
+    form.append('map', JSON.stringify(fileMap));
+
+    await Promise.all(
+      resolvedFiles.map(async ([, contents], i) => {
+        const { filename, mimetype, createReadStream } = contents;
+        const readStream = await createReadStream();
+        const buffer = await this.onReadStream(readStream);
+        form.append(i, buffer, { filename, contentType: mimetype });
+      })
+    );
+
+    // Respect incoming http headers (eg, apollo-federation-include-trace).
+
+    const headers = (request.http && request.http.headers) || new Headers();
+
+    form.getLength(function(err, length) {
+      headers.set('Content-Length', length);
+    });
+
+    Object.entries(form.getHeaders() || {}).forEach(([k, value]) => {
+      headers.set(k, value);
+    });
+
+    request.http = {
+      method: 'POST',
+      url: this.url,
+      headers,
+    };
+    if (this.willSendRequest) {
+      await this.willSendRequest({ request, context });
+    }
+
+    const options = {
+      ...request.http,
+      body: form,
+    };
+
+    const httpRequest = new Request(request.http.url, options);
+
+    try {
+      const httpResponse = await fetch(httpRequest);
+
+      const body = await this.didReceiveResponse(httpResponse, httpRequest);
+
+      if (!isObject(body)) {
+        throw new Error(`Expected JSON response body, but received: ${body}`);
+      }
+      const response = {
+        ...body,
+        http: httpResponse,
+      };
+
+      return response;
+    } catch (error) {
+      this.didEncounterError(error, httpRequest);
+      throw error;
+    }
+  }
+  extract(obj) {
+    const files = [];
+
+    const _extract = (obj, keys) =>
+      Object.entries(obj || {}).forEach(([k, value]) => {
+        const key = keys ? `${keys}.${k}` : k;
+        if (value instanceof Promise) {
+          return files.push([key, value]);
+        }
+        if (value instanceof Object) {
+          return _extract(value, key);
+        }
+      });
+    _extract(obj);
+    return files;
+  }
+  onReadStream = readStream => {
+    return new Promise((resolve, reject) => {
+      var buffers = [];
+      readStream.on('data', function(data) {
+        buffers.push(data);
+      });
+      readStream.on('end', function() {
+        var actualContents = Buffer.concat(buffers);
+
+        resolve(actualContents);
+      });
+      readStream.on('error', function(err) {
+        reject(err);
+      });
+    });
+  };
+}