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Sync Request API

Last updated: 2022-07-29 14:13:39

    Feature Description

    The file preview feature allows generating images from multiple types of files for preview and performing basic processing operations on the output images synchronously. It addresses the display problems of file content on webpages and enables easy online file preview on PC, app, and other terminals. It is widely suitable for diverse business scenarios, such as online education, enterprise OA, and website transcoding.

    Note:

    • To use this feature, you need to click File Processing on the management page of a bucket in the CI console, find the File Preview configuration item, and toggle it on. Then, you can call a specific file preview API to preview files in the bucket synchronously or asynchronously.
    • File preview is a paid feature. For billing details, see File Processing Fees.
    • The conversion logic of file transcoding is the same as that of local printing. If you need to change the conversion orientation (such as outputting an Excel file with many columns horizontally to one page), you need to change the source file print settings.

    Request

    Sample request

    GET /<ObjectKey>?ci-process=doc-preview&page=<page>&srcType=<srcType>&ImageParams=<ImageParams> HTTP/1.1
    Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
    Date: GMT Date
    Authorization: Auth String
    
    Note:

    • Authorization: Auth String (for more information, see Request Signature).
    • When this feature is used by a sub-account, relevant permissions must be granted. For more information, see Authorization Granularity.
    • For private buckets, the request needs to carry the signature for file download.

    Request headers

    This API only uses common request headers. For more information, see Common Request Headers.

    Common request parameters

    Parameter Description Type Required
    ObjectKey Object name, such as folder/document.pdf. String Yes
    ci-process CI's processing capability, which is fixed at doc-preview for file preview. String Yes
    srcType Source data type. Currently, the file conversion feature determines the source data type according to the file extension of the COS object. If the object has no extension, you can set this value. String No
    page Number of the page to be converted, which is counted from 1 by default. For spreadsheets, page indicates to convert the xth image in the xth sheet. Int No
    dstType Type of the output target file. Valid values:
  • png
  • jpg
  • pdf (the page number cannot be selected, and the page parameter does not take effect)
  • txt
    If the input file format cannot be recognized, the jpg format will be used by default.
  • String No
    password Password to open the Office file. If you need to convert a password-protected file, set this field. String No
    comment Whether to hide comments and apply track changes. 0: hide comments and apply track changes; 1: show comments and track changes. Default value: 0. Int No

    Parameters for spreadsheet files (Excel)

    Parameter Description Type Required
    sheet Sheet parameter, indicating to convert the xth sheet. Default value: 1. Int No
    excelPaperDirection Paper orientation of the spreadsheet. 0: vertical; other values: horizontal. Default value: 0. Int No
    excelRow A value of 1 indicates to put all rows on one page for formatting. Default value: 0. Int No
    excelCol A value of 1 indicates to put all columns on one page for formatting. Default value: 0. Int No
    excelPaperSize Paper (canvas) size. Valid values: 0 (A4), 1 (A2), 2 (A0). Default value: 0. This parameter should be used together with excelRow or excelCol. Int No

    Parameters for transcoding into .txt files

    Parameter Description Type Required
    txtPagination Whether to convert to long text. When this parameter is set to true, the text in the pages to be exported can be combined before export, and the pagination range can be controlled by Ranges. The default value is false, indicating to generate .txt files by page. This parameter takes effect only if ExportType is txt. Bool No

    Parameters for transcoding to .png/.jpg images

    Name Description Type Required
    ImageParams Processing parameters for the output image. All parameters of basic image processing are supported. To specify multiple parameters, separate them with pipeline operators. In this way, the image can be processed by multiple parameters in sequence in the same request. String No
    quality Quality of the generated preview image. Value range: [1, 100]. Default value: 100. For example, if the value is 100, the quality of the generated image will be 100%. Int No
    scale Scaling parameter of the preview image. Value range: [10, 200]. Default value: 100. For example, if the value is 200, the image will be scaled up (enlarged) by 200%. Int No
    imageDpi Renders the image according to the specified DPI. This parameter works together with scale. Value range: 96–600. Default value: 96. The width of the output image must be less than 65500 px. Int No
    Note:

    • Currently supported input file types include:
    • Presentation files: PPTX, PPT, POT, POTX, PPS, PPSX, DPS, DPT, PPTM, POTM, PPSM.
    • Text files: DOC, DOT, WPS, WPT, DOCX, DOTX, DOCM, DOTM.
    • Spreadsheet files: XLS, XLT, ET, ETT, XLSX, XLTX, CSV, XLSB, XLSM, XLTM, ETS.
      A spreadsheet file may be split into multiple pages, with multiple images generated.
    • Other files: PDF, LRC, C, CPP, H, ASM, S, JAVA, ASP, BAT, BAS, PRG, CMD, RTF, TXT, LOG, XML, HTM, HTML.
    • The input file size cannot exceed 200 MB.
    • The number of pages in the input file cannot exceed 5,000.

    Request body

    The request body of this request is empty.

    Response

    Response headers

    This API only returns common response headers. For more information, see Common Response Headers.

    Response parameter description

    Parameter Description Type
    X-Total-Page Total number of pages in the file (or images converted from sheets in the spreadsheet file) returned in the HTTP header. This value will be empty in case of an exception. Int
    Content-Type Different values will be returned based on the actual image format, such as image/jpeg and image/webp. It is okay to keep the current value in case of an exception. String
    X-ErrNo The error code returned in case of an exception, which can be viewed in the HTTP header. String
    X-Total-Sheet Total number of sheets in the spreadsheet file returned in the HTTP header. Int
    X-Sheet-Name Name of the current sheet in the spreadsheet file returned in the HTTP header. String

    Error codes

    There are no special error messages for this request. For common error messages, see Error Codes.

    Samples

    Sample 1: Previewing a general file

    Request

    GET /sample.pdf?ci-process=doc-preview&page=1 HTTP/1.1
    Host: examplebucket-1250000000.cos.ap-shanghai.myqcloud.com
    

    Response 1: Preview succeeds

    HTTP/1.1 200 OK
    Content-Type: image/jpeg
    Content-Length: 645
    Date: Tue, 03 Apr 2018 09:06:16 GMT
    X-Total-Page: 100
    [Image data after transcoding]
    

    Response 2: The file does not exist

    HTTP/1.1 404 OK
    Connection: close
    Content-Length: 455
    Content-Type: application/xml
    Date: Thu, 09 Apr 2020 13:44:52 GMT
    X-ErrNo: -3004
    

    Response 3: The specified page does not exist

    HTTP/1.1 404 OK
    Connection: close
    Content-Length: 455
    Content-Type: application/xml
    Date: Thu, 09 Apr 2020 13:44:52 GMT
    X-ErrNo: -3013
    

    Sample 2: Previewing a file and processing the image by scaling it and adding a text watermark

    Request

    GET /sample.pdf?ci-process=doc-preview&page=1&ImageParams=imageMogr2/thumbnail/!50p|watermark/2/text/5pWw5o2u5LiH6LGh/fill/I0ZGRkZGRg==/fontsize/30/dx/20/dy/20 HTTP/1.1
    Host: examplebucket-1250000000.cos.ap-shanghai.myqcloud.com
    

    Response 1: Preview succeeds

    HTTP/1.1 200 OK
    Content-Type: image/jpeg
    Content-Length: 645
    Date: Tue, 03 Apr 2018 09:06:16 GMT
    X-Total-Page: 100
    [Image data after transcoding]
    

    Response 2: The file does not exist

    HTTP/1.1 404 OK
    Connection: close
    Content-Length: 455
    Content-Type: application/xml
    Date: Thu, 09 Apr 2020 13:44:52 GMT
    X-ErrNo: -3004
    

    Response 3: The specified page does not exist

    HTTP/1.1 404 OK
    Connection: close
    Content-Length: 455
    Content-Type: application/xml
    Date: Thu, 09 Apr 2020 13:44:52 GMT
    X-ErrNo: -3013
    
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