FileService

Overview
SERVICE
This class is a "service" and it is automatically injected if declared as a member in the constructor of the consuming class. 
 - See the constructor section below for details
-  See the Automatic Instance Injection page for  details on the topic
The FileService class provides methods to work with files 
Properties
Methods
Constructor
App Types
Properties
No properties
Methods
​fileWrite​
​fileRead​
​fileDelete​
​fileExists​
​getDirFiles​
Constructor
Don't instantiate directly instances of the SqlQueryServiceclass. 
SqlQueryService instances are automatically injected by Dynamics Mobile framework.
import { View, SqlQueryService } from '$dms';
import { Customer } from '$dms-bo';
​
@View()
export class MyView {
​
  constructor(
    //we need to only declare the member
    private SqlQueryService: SqlQueryService
  ){
  
  }
​
  async load(){      
    //we can now use the injected instance 
    let  value = await this.SqlQueryService.execute(`select * from ${Customer.boTableName}}`);   
  }
​
}
App Types
  📳 Mobile
  🌐 Backend
There is a difference in the behaviour of the FileService API in mobile and backend apps. Read the File Access documentation for more details 
​▶ fileWrite(fileName: string, fileContent:string): Promise<void>
Description
Parameters
Returns
Example
Description
fileWrite method creates new file with given filename and filecontent. The method will overwrite the file if it already exists without throwing error

Parameters
fileName: string - file name including directory and extension. myfolder/myfile.json
fileContent: string - string content encoded in utf-8
Returns
void
Example
​
import { FileService } from '@dms';
import { Customer } from '@dms-bo';
​
...
const customers = await Customer.query().executeSelect();
await this.FileService.fileWrite('customers/list.json', JSON.stringify(customers));
fileRead(fileName: string): Promise<string>
Description
Parameters
Returns
Example
Description
fileRead method reads and returns the content of existing file by given filename. The method throws error if the file does not exists.
Parameters
fileName: string - the name of the file including the folder and file extension - myfolder/myfile.json
Returns
string content read from the file encoded in utf-8
Example
import { FileService } from '@dms';
import { Customer } from '@dms-bo';
​
...
const content = await this.FileService.fileRead('customers/list.json');
const customers = JSON.parse(content);
​
fileDelete(fileName: string): Promise<void>
Description
Parameters
Returns
Example
Description
fileDelete method deletes a file by given filename. The method will not throw error if the file does not exists.
Parameters
fileName: string - the name of the file including the folder and file extension - myfolder/myfile.json
Returns
void
Example
import { FileService } from '@dms';
import { Customer } from '@dms-bo';
​
...
await this.FileService.fileDelete('customers/list.json');
​
fileExists(fileName: string): Promise<boolean>
Description
Parameters
Returns
Example
Description
fileExists method returns true if the file with the given filename exists.
Parameters
fileName: string - the name of the file including the folder and file extension - myfolder/myfile.json
Returns
true if the file exists
false if the file does not exists
Example
import { FileService } from '@dms';
import { Customer } from '@dms-bo';
​
...
const exists = await this.FileService.fileExists('customers/list.json');
if(exists){
    const content = await this.FileService.fileRead('customers/list.json');
}
​
​
getDirFiles(folder: string): Promise<Array<string>>
Description
Parameters
Returns
Example
Description
getDirFiles method returns list of files contained in the given folder.
Parameters
folder: string - the full name of the file folder- myfolder/subfolder
Returns
List of strings, where each array element is a full file path for a file contained in the given folder.
Example
import { FileService } from '@dms';
import { Customer } from '@dms-bo';
​
...
const files = await this.FileService.getDirFiles('customers');
let combinedContent = '';
for(let i=0;i<files.length;i++){
    const filePath = files[i];
    const content = await this.FileService.readFile(filePath);
    combinedContent+=content;
}
​
​
SqlQueryService
DeviceService
Last updated 2 months ago
FileService

Overview

​▶ fileWrite(fileName: string, fileContent:string): Promise<void>

fileRead(fileName: string): Promise<string>

fileDelete(fileName: string): Promise<void>

fileExists(fileName: string): Promise<boolean>

getDirFiles(folder: string): Promise<Array<string>>

▶ fileWrite(fileName: string, fileContent:string): Promise<void>
