Hi,

I'm trying to update a file in a package. I naively tried to simply re-add it after modification but this returns the following:

a package shall not contain equivalent part names

Is it possible to delete a part in the package or even just update it with a modified version?

Hi,

I have a problem reopening an existing file and adding further parts to it.

I reopen the file with the following:

p.reader, err = opc.OpenReader(outputFilePath)
p.writer, err = opc.NewWriterFromReader(&bytes.Buffer{}, p.reader.Reader)

and I get no error. In the debugger I can also see that the correct file is opened with files added previously.

However, when I attach new files using:

name := opc.NormalizePartName(contentType.PackagePath + "/" + fileName)
part, err := p.writer.Create(name, contentType.Value)
bytes, err := ioutil.ReadFile(contentFilePath)
// Write content to the part.
part.Write(bytes)

I see in the debugger that everything is added to the object but nothing is finally added to the file.

I also tried

part, err := p.writer.CreatePart(&opc.Part{
        Name:        name,
	ContentType: contentType.Value,
}, opc.CompressionNormal)

instead of

part, _ := p.writer.Create(name, contentType.Value)

but it has the same effect.

What am I doing wrong or is there a bug?

According to Notes on the W3C XML Schemas for Qualified Dublin Core, the Core properties dates should be serialized with xsi:type="dcterms:W3CDTF" like dcterms:created and dcterms:modified in the below example:

<?xml version="1.0" encoding="UTF-8"?>
<coreProperties xmlns="http://schemas.openxmlformats.org/package/2006/metadata/core-properties"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:dcmitype="http://purl.org/dc/dcmitype/"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <dcterms:created xsi:type="dcterms:W3CDTF">2020-10-15T04:05:00Z</dcterms:created>
    <dc:creator>Microsoft Office User</dc:creator>
    <lastModifiedBy>Microsoft Office User</lastModifiedBy>
    <dcterms:modified xsi:type="dcterms:W3CDTF">2020-10-15T04:07:00Z</dcterms:modified>
    <revision>2</revision>
</coreProperties>

Microsoft Office validator complains when xsi:type="dcterms:W3CDTF" is missing

MS Office does not open a document when Content_Types.xml contains an override part of itself

    <Override PartName="/[Content_Types].xml" ContentType="text/xml"></Override>

• Part names with valid IRI syntax are now accepted when writing a package
• NormalizePartName correctly escape IRI and URI sub-delims and other no-reserved characters

NewWriterFromReader is a helper function that created a new Writer with the content of a Reader. This facilitate the task of modifying core properties and package relationships and appending parts to a package.

New CoreProperties member: RelationshipID. Like PartName, it is not serialized in the XML.

Microsoft Office requires the relationship ID values honoring the pattern rIdNNN where NNN is a positive number. This change will allow users to predefine the ID to bypass

According to the specs:

The package implementer might allow a TargetMode to be provided by a producer. [O1.5] The TargetMode indicates whether or not the target describes a resource inside the package or outside the package. The valid values, in the Relationships schema, are Internal and External. The default value is Internal. When set to Internal, the Target attribute shall be a relative reference and that reference is interpreted relative to the “parent” part. For package relationships, the package implementer shall resolve relative references in the Target attribute against the pack URI that identifies the entire package resource. [M1.29] For more information, see Annex B.

func relativePart() {
	filename := "test_files/relative_parts.zip"
	f, _ := os.Create(filename)
	w := opc.NewWriter(f)

	contentType := "plain/text"
	names := []string{"one", "two", "three", "four"}

	var parts []*opc.Part

	prev := ""
	for _, relativeName := range names {
		name := prev + "/" + relativeName + ".txt"
		parts = append(parts, &opc.Part{Name: name, ContentType: contentType})
		prev = prev + "/" + relativeName
	}
	var i int
	for i = 0; i < len(names)-1; i++ {
		parts[i].Relationships = append(parts[i].Relationships,
			&opc.Relationship{ID: strconv.Itoa(i), TargetMode: opc.ModeInternal, TargetURI: names[i+1], Type: contentType})
		pw, _ := w.CreatePart(parts[i], opc.CompressionNone)
		_, _ = pw.Write([]byte(names[i]))
	}
	pw, _ := w.CreatePart(parts[i], opc.CompressionNone)
	pw.Write([]byte(names[i]))

	w.Close()
}

The above code creates a package with absolutes Targets that actually are wrong. Probably the normalizeTargetURI() needs some refactory.

An example of the wrong absolute path at _one/two/rels/three.txt.rels

<?xml version="1.0" encoding="UTF-8"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
    <Relationship Id="2" Type="plain/text" Target="/four"></Relationship>
</Relationships>