Generate a list of all fields and data types for a given object and send the metadata in CSV format via email

listObjectFields.java

// README: This is the only line you need to edit (generally speaking)
// This is the object for which I want to extract the field describes.
// Running this script will send the resulting field list to your user's email,
// with the fields as an attached CSV file.
Schema.DescribeSObjectResult objectDescribe = Schema.SObjectType.OpportunityLineItem;

/**
 * Wrapper class to return CSV rows
 */
public class FieldCsvWriter {
    private Schema.DescribeFieldResult fieldDescribe { get; set; }
    private Schema.DescribeSObjectResult objectDescribe { get; set; }
    
    public FieldCsvWriter(
        Schema.DescribeFieldResult fieldDescribe,
        Schema.DescribeSObjectResult objectDescribe
    ) {
        this.fieldDescribe = fieldDescribe;
        this.objectDescribe = objectDescribe;
    }
    
    public String escape(String value) {
        return '"' + value + '"';
    }
    
    public List<String> getCsvRow() {
        
        // Construct the list
        List<String> row = new List<String>();
        
        row.add(this.escape(this.getRowId()));
        row.add(this.escape(getName()));
        row.add(this.escape(this.getObjectUniqueName()));
        row.add(this.escape(this.getLabel()));
        row.add(this.escape(this.getDataType()));
        
        // Return the row
        return row;
    }
    
    private String getDataType() {
        String dataType = '#UNKNOWN';
        
        // Get Display Type for comparison
        Schema.DisplayType fieldDisplayType = this.fieldDescribe.getType();
        
        if (fieldDisplayType == Schema.DisplayType.ADDRESS) {
            dataType = 'Address';
        }
        else if (fieldDisplayType == Schema.DisplayType.BOOLEAN) {
            dataType = 'Checkbox';
        }
        else if (fieldDisplayType == Schema.DisplayType.CURRENCY) {
            dataType = 'Currency(';
            dataType += this.fieldDescribe.getPrecision();
            dataType += ', ';
            dataType += this.fieldDescribe.getScale();
            dataType += ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.DATE) {
            dataType = 'Date';
        }
        else if (fieldDisplayType == Schema.DisplayType.DATETIME) {
            dataType = 'Date/Time';
        }
        else if (fieldDisplayType == Schema.DisplayType.DOUBLE) {
            dataType = 'Number(';
            dataType += this.fieldDescribe.getPrecision();
            dataType += ', ';
            dataType += this.fieldDescribe.getScale();
            dataType += ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.EMAIL) {
            dataType = 'Email';
        }
        else if (fieldDisplayType == Schema.DisplayType.ID) {
            dataType = 'Lookup(' + objectDescribe.getLabel() + ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.INTEGER) {
            dataType = 'Number(';
            dataType += this.fieldDescribe.getPrecision();
            dataType += ', ';
            dataType += 0;
            dataType += ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.PHONE) {
            dataType = 'Phone';
        }
        else if (fieldDisplayType == Schema.DisplayType.PERCENT) {
            dataType = 'Percent(';
            dataType += this.fieldDescribe.getPrecision();
            dataType += ', ';
            dataType += this.fieldDescribe.getScale();
            dataType += ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.PICKLIST) {
            dataType = 'Picklist';
        }
        else if (fieldDisplayType == Schema.DisplayType.REFERENCE) {
            
            // TODO: Support polymorphic fields
            dataType = 'Lookup(' + this.fieldDescribe.getReferenceTo()[0].getDescribe().getLabel() + ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.STRING) {
            dataType = 'Text(' + this.fieldDescribe.getLength() + ')';
        }
        else if (fieldDisplayType == Schema.DisplayType.TEXTAREA) {
            dataType = 'Text Area';
            
            // Check to see whether it's actually a Long Text Area
            if (this.fieldDescribe.getLength() > 255) {
                dataType = 'Long Text Area(' + this.fieldDescribe.getLength() + ')';
            }
        }
        else if (fieldDisplayType == Schema.DisplayType.URL) {
            dataType = 'URL(' + this.fieldDescribe.getLength() + ')';
        }
        else {
            dataType += '|' + fieldDisplayType.name();
        }
        
        // Return the data type
        return dataType;
    }
    
    private String getLabel() {
        return fieldDescribe.getLabel();
    }
    
    private String getName() {
        return fieldDescribe.getName();
    }
    
    private String getObjectUniqueName() {
        return 'sfdc.' + objectDescribe.getName();
    }
    
    private String getRowId() {
        return '';
    }
}

/**
 * Writer to produce CSV text
 */
public class CsvWriter {
    private String fieldDelimiter { get; set; }
    private String recordDelimiter { get; set; }
    private List<List<String>> rows { get; set; }
    
    public CsvWriter(List<List<String>> rows) {
        this.rows = rows;
        this.fieldDelimiter = ',';
        this.recordDelimiter = '\n';
    }
    
    public String getPlainText() {
        
        // Collapse the nested list into a single list
        List<String> rowTexts = new List<String>();
        
        for (List<String> eachRow : this.rows) {
            rowTexts.add(String.join(eachRow, this.fieldDelimiter));
        }
        
        // Return the joined rows
        return String.join(rowTexts, this.recordDelimiter);
    }
}

// Get a list of all the fields
List<List<String>> csvRows = new List<List<String>>();

// Compile the list into CSV rows,
// adding each row into the master list to send
Map<String, Schema.SObjectField> fieldMap = objectDescribe.fields.getMap();

for (Schema.SObjectField eachField : fieldMap.values()) {
    
    // Construct the field writer
    FieldCsvWriter writer = new FieldCsvWriter(
        eachField.getDescribe(),
        objectDescribe
    );
    
    // Dump the field info to a list of text
    csvRows.add(writer.getCsvRow());
}

// Construct the email
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();

mail.setSubject(objectDescribe.getName() + ' fields');
mail.setPlainTextBody('Attached as CSV');

Messaging.EmailFileAttachment csvFile =
    new Messaging.EmailFileAttachment();
csvFile.filename = objectDescribe.getName() + '.csv';
csvFile.contenttype = 'text/csv';
csvFile.body = Blob.valueOf(new CsvWriter(csvRows).getPlainText());

// Attach the CSV file
mail.setFileAttachments(new List<Messaging.EmailFileAttachment> { csvFile });

// Send the email to myself
mail.setTargetObjectId(UserInfo.getUserId());
mail.setSaveAsActivity(false);

Messaging.sendEmail(new List<Messaging.Email> { mail });